この作品は、レオナルドP.チャモロのスタートアップパッケージの一部として機械科学・工学、イリノイ大学アーバナ・シャンペーン校、学部によってサポートされていました。

<ol>
	<li>Wygnanski, I., Fiedler, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Some measurements in the self preserving jet. , (1968).</li><li>Rajaratnam, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Turbulent jets. , (1976).</li><li>Panchapakesan, N., Lumley, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Turbulence+measurements+in+axisymmetric+jets+of+air+and+helium.+Part+1.+Air+jet.">Turbulence measurements in axisymmetric jets of air and helium. Part 1. Air jet.</a> J Fluid Mech. 246, 197-223 (1993).</li><li>Hussein, H. J., Capp, S. P., George, W. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Velocity+measurements+in+a+high-Reynolds-number,+momentum-conserving,+axisymmetric,+turbulent+jet.">Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet.</a> J Fluid Mech. 258, 31-75 (1994).</li><li>Yule, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+structure+in+the+mixing+layer+of+a+round+jet.">Large-scale structure in the mixing layer of a round jet.</a> J Fluid Mech. 89, 413-432 (1978).</li><li>Yule, A., Chigier, N., Ralph, S., Boulderstone, R., Venturag, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combustion-transition+interaction+in+a+jet+flame.">Combustion-transition interaction in a jet flame.</a> AIAA Journal. 19, 752-760 (1981).</li><li>Quinn, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Upstream+nozzle+shaping+effects+on+near+field+flow+in+round+turbulent+free+jets.">Upstream nozzle shaping effects on near field flow in round turbulent free jets.</a> Eur J Mech B-Fluid. 25, 279-301 (2006).</li><li>Mi, J., Nathan, G. J., Luxton, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Centreline+mixing+characteristics+of+jets+from+nine+differently+shaped+nozzles.">Centreline mixing characteristics of jets from nine differently shaped nozzles.</a> Exp Fluids. 28, 93-94 (2000).</li><li>Liepmann, D., Gharib, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+streamwise+vorticity+in+the+near-field+entrainment+of+round+jets.">The role of streamwise vorticity in the near-field entrainment of round jets.</a> J Fluid Mech. 245, 643-668 (1992).</li><li>Oh, S. K., Shin, H. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+visualization+study+on+the+effect+of+forcing+amplitude+on+tone-excited+isothermal+jets+and+jet+diffusion+flames.">A visualization study on the effect of forcing amplitude on tone-excited isothermal jets and jet diffusion flames.</a> Int J Energ Res. 22, 343-354 (1998).</li><li>Cenedese, A., Doglia, G., Romano, G., De Michele, G., Tanzini, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LDA+and+PIV+velocity+measurements+in+free+jets.">LDA and PIV velocity measurements in free jets.</a> Exp Therm Fluid Sci. 9, 125-134 (1994).</li><li>Wang, H., Peng, X., Lin, W., Pan, C., Wang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bubble-top+jet+flow+on+microwires.">Bubble-top jet flow on microwires.</a> Int J Heat Mass Tran. 47, 2891-2900 (2004).</li><li>Shestakov, M. V., Tokarev, M. P., Markovich, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+Flow+Dynamics+in+a+Turbulent+Slot+Jet:+Time-resolved+Tomographic+PIV+Measurements.">3D Flow Dynamics in a Turbulent Slot Jet: Time-resolved Tomographic PIV Measurements.</a> 17th Int Symp on Applications of Laser Techniques to Fluid Mechanics. , (2014).</li><li>Scarano, F., Bryon, K., Violato, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-resolved+analysis+of+circular+and+chevron+jets+transition+by+tomo-PIV.">Time-resolved analysis of circular and chevron jets transition by tomo-PIV.</a> 15th Int Symp on Applications of Laser Techniques to Fluid Mechanics. , (2010).</li><li>Holzner, M., Liberzon, A., Nikitin, N., Kinzelbach, W., Tsinober, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small-scale+aspects+of+flows+in+proximity+of+the+turbulent/nonturbulent+interface.">Small-scale aspects of flows in proximity of the turbulent/nonturbulent interface.</a> Phys Fluids. 19, 071702 (2007).</li><li>Holzner, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Lagrangian+investigation+of+the+small-scale+features+of+turbulent+entrainment+through+particle+tracking+and+direct+numerical+simulation.">A Lagrangian investigation of the small-scale features of turbulent entrainment through particle tracking and direct numerical simulation.</a> J Fluid Mech. 598, 465-475 (2008).</li><li>Chang, T. P., Wilcox, N. A., Tatterson, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+image+processing+to+the+analysis+of+three-dimensional+flow+fields.">Application of image processing to the analysis of three-dimensional flow fields.</a> Opt Eng. 23, 283-287 (1984).</li><li>Racca, R., Dewey, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+automatic+particle+tracking+in+a+three-dimensional+flow+field.">A method for automatic particle tracking in a three-dimensional flow field.</a> Exp Fluids. 6, 25-32 (1988).</li><li>Maas, H. G., Gruen, D., Papantoniou, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle+tracking+velocimetry+in+three-dimensional+flows.">Particle tracking velocimetry in three-dimensional flows.</a> Exp Fluids. 15, 133-146 (1993).</li><li>Kasagi, N., Matsunaga, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+particle+tracking+velocimetry+measurement+of+turbulence+statistics+and+energy+budget+in+a+backward-facing+step+flow.">Three-dimensional particle tracking velocimetry measurement of turbulence statistics and energy budget in a backward-facing step flow.</a> Int J Heat Fluid Fl. 16, 477-485 (1995).</li><li>Virant, M., Dracos, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+PTV+and+its+application+on+Lagrangian+motion.">3D PTV and its application on Lagrangian motion.</a> Meas Sci Technol. 8, 1539 (1997).</li><li>Willneff, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> A spatio-temporal matching algorithm for 3 D particle tracking velocimetry. , (2003).</li><li>Rosi, G. A., Sherry, M., Kinzel, M., Rival, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+the+lower+log+region+of+the+atmospheric+surface+layer+via+large-scale+particle+tracking+velocimetry.">Characterizing the lower log region of the atmospheric surface layer via large-scale particle tracking velocimetry.</a> Exp Fluid. 55, 1-10 (2014).</li><li>Fu, S., Biwole, P. H., Mathis, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle+Tracking+Velocimetry+for+indoor+airflow+field:+A+review.">Particle Tracking Velocimetry for indoor airflow field: A review.</a> Build Environ. 87, 34-44 (2015).</li><li>Kolaas, J., Jensen, A., Mielnik, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+and+measurements+of+flows+in+micro+silicon+Y-channels.">Visualization and measurements of flows in micro silicon Y-channels.</a> Eur Phys J E. 36, 1-11 (2013).</li><li>G&#252;lan, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+of+aortic+flow+in+the+ascending+aortavia+Particle+Tracking+Velocimetry.">Experimental study of aortic flow in the ascending aortavia Particle Tracking Velocimetry.</a> Exp Fluids. 53, 1469-1485 (2012).</li><li>Mei, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Velocity+fidelity+of+flow+tracer+particles.">Velocity fidelity of flow tracer particles.</a> Exp Fluids. 22, 1-13 (1996).</li><li>Tropea, C., Yarin, A. L., Foss, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Springer handbook of experimental fluid mechanics. 1, (2007).</li><li>Melling, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracer+particles+and+seeding+for+particle+image+velocimetry.">Tracer particles and seeding for particle image velocimetry.</a> Meas Sci Technol. 8, 1406 (1997).</li><li>Hering, F., Leue, C., Wierzimok, D., J&#228;hne, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle+tracking+velocimetry+beneath+water+waves.+Part+I:+visualization+and+tracking+algorithms.">Particle tracking velocimetry beneath water waves. Part I: visualization and tracking algorithms.</a> Exp Fluids. 23, 472-482 (1997).</li><li>Biferale, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lagrangian+structure+functions+in+turbulence:+A+quantitative+comparison+between+experiment+and+direct+numerical+simulation.">Lagrangian structure functions in turbulence: A quantitative comparison between experiment and direct numerical simulation.</a> Phys Fluids. 20, 065103 (2008).</li><li>L&#252;thi, B., Tsinober, A., Kinzelbach, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lagrangian+measurement+of+vorticity+dynamics+in+turbulent+flow.">Lagrangian measurement of vorticity dynamics in turbulent flow.</a> J Fluid mech. 528, 87-118 (2005).</li><li>Hoyer, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3d+scanning+particle+tracking+velocimetry.">3d scanning particle tracking velocimetry.</a> Exp Fluids. 39, 923-934 (2005).</li><li>Kim, J. -. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Three-dimensional particle tracking velocimetry for turbulence applications. , (2015).</li><li>L&#252;thi, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+aspects+of+strain,+vorticity+and+material+element+dynamics+as+measured+with+3D+particle+tracking+velocimetry+in+a+turbulent+flow.">Some aspects of strain, vorticity and material element dynamics as measured with 3D particle tracking velocimetry in a turbulent flow.</a> ETH Z&#252;rich. , (2002).</li><li>Pope, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Turbulent flows. , (2000).</li></ol>

著者は、彼らが競合する経済的利害関係を持っていないことを宣言します。

<html> 3D-PTVは下層大気25、室内空気分布26でこのような大規模乱流運動として乱流の様々な複雑な物理現象を解明するための大きな可能性を秘めている、または拍動性は、多くの他の中大動脈トポロジ28に流れます。しかし、その利点と限界についての理解だけでなく、経験がその可能性を最大限にすることが不可欠です。トライアルフレームレート、照明光源、G＆Bレ?...

乱流ジェット流は、エンジニアリング用途に遍在しています。このような流れの詳細な特性は、電子マイクロスケールデバイスに大規模な環境放電システムから及ぶ実用上の問題の広い範囲で非常に重要です。 4 -ための広範なアプリケーションの数に与える影響を、ジェットフローは、深さ1に研究されています。熱線流速計4を含むいくつかの実験技術- 8は 、レーザードップラー流速計（LDV）4,9 - 12、及び粒子画像流速測定（PIV）12を- 16は 、噴流を特徴付けるために使用されてきたレイノルズ数と境界の広い範囲に流れます条件。最近、いくつかの研究では、ジェットの乱流/非乱流インタフェースは17、18を流れて勉強する3D-PTVを使用して作られてきました。 3D-PTVは、複雑な乱流Fiのを記述するために特に適した技術であります異なる視点からELDより。これは、マルチビュー立体視を用いて、基準のラグランジュフレームにボリューム内の粒子軌道の再構成を可能にします。技術は最初チャン19によって導入され、さらにRaccaとデューイ20によって開発されました。 24 -それ以来、多くの改良は、3D-PTVアルゴリズムと実験21日に行われています。これらの成果と以前の作品では、システムが正常に4 MX 2 MX 2メートル25、室内の気流場26のドメインにこのような大規模な流体運動など様々な流体現象を研究するために使用されてきた、拍動は27と大動脈の血流28を流れ、 。 3D-PTV計測の動作原理は、データ収集システムのセットアップ、記録/前処理、キャリブレーション、3D対応、時間追跡および後処理から成ります。正確なキャリブレーションは、粒子の位置を正確に検出することが可能秒。以上の3つの画像ビューで検出された粒子の対応はエピポーラ幾何学に基づいた3Dパーティクル位置の再構築を可能にします。連続する画像フレームからの結合は、粒子の軌跡S（t）を定義する一時的な追跡をもたらします。 3D-PTVシステムの最適化は、多粒子トレーサビリティの尤度を最大にするために不可欠です。 最適化の最初のステップは、高速カメラ、照明源とシード粒子の特徴を含む適切なデータ収集システムを取得することです。調査体積の大きさに伴ってカメラの解像度は、画素サイズと単一の画素よりも大きくする必要があり、従って、必要なシード粒子のサイズを定義します。検出された粒子の重心は、輝度21で重み付け粒子画素の平均位置を取ることによってサブピクセル精度で推定されます。カメラのフレームレートは密接associatありますレイノルズ数と検出された粒子をリンクする機能とエド。より高いフレームレートが速い流れまたは平均画像間の変位は粒子の平均分離を超える場合、追跡がより困難になるので、粒子の多くを解決することを可能にします。 シャッター速度、絞り、感度は画像キャプチャで考慮すべき3つの要因です。シャッター速度は、粒子の重心位置の不確実性を低下させ、粒子、周りにぼかし最小限にするのに十分高速である必要があります。カメラの絞りは、ボリュームの外側に粒子を検出する確率を低減するために調査体積のフィールドの深さに調整されるべきです。カメラの最大感度が固定されているので、フレームレートが増加すると、粒子を照明​​するために要求される必要な光は、それに応じて増加するはずです。 PIVとは異なり、複雑な光学設定と高出力レーザーは厳密に限り、光源が十分にスキャットであ​​るとして、3D-PTVで必要とされていませんカメラにトレーサー粒子から結。連続LEDやハロゲンライトは同期21の必要性を回避良い費用対効果の高いオプションです。 3D-PTVでは、他のオプティカルフロー測定技術と同様に、トレーサー粒子速度は、局所瞬間流速29であると仮定されます。しかし、これはnullを直径と慣性の理想的なトレーサーのための唯一のケースです。トレーサー粒子は、カメラによって捕捉されるのに十分大きくなければなりません。有限の粒子の忠実度は、粒子の緩和時間スケール比と関心の乱流構造の時間尺度、すなわち 、ストークス数S tで決定することができます。一般的に、S tは S Tの1よりも実質的に小さくなければならない≤0.1フロートラッキング誤差は1％未満である30。より綿密な議論がメイらに記載されています29 - 。31 </sup&gt;。 3D-PTVの実験のための推奨される粒径は、光源とカメラの感度によって異なります。ハロゲンまたは照明光源としてLEDが点灯して、比較的大きな粒子が使用される（ 例えば 、50〜200ミクロン）32、より小さな粒子（ 例えば 1~50ミクロン）33に対し、 図34は、高出力レーザー（ 例えば、80〜100ワットで使用することができCWレーザー）。所定の波長の光に対して高い反射率を有する粒子が、ハロゲンライトの下でコーティングされた銀のように、画像にその足跡を増幅することができます。播種密度は、成功した3D-PTV測定のための別の重要なパラメータです。粒子の過剰な数が対応関係を確立し、追跡中の曖昧さを引き起こす一方で、いくつかの粒子は、軌道の低い数になります。対応関係を確立する上で曖昧さが重なり、粒子と定義されたエピポーラ線に沿って複数の候補を検出することが含まれます。追尾処理において、高いseedinによる曖昧<html> G濃度があるため、粒子の比較的短い平均分離を発生しました。 第二段階は、画像品質を向上させるために、記録/前処理で最適な設定です。そのようなゲインと黒レベル（G＆B）のような写真の設定は、画像品質を最適化する上で重要な役割を果たしています。ゲインは、画像の明るさを増幅するのに対し、黒レベルは、画像の最も暗い部分の明るさのレベルを定義します。 G＆Bレベルのわずかな変化が著しく、トレーサビリティの可能性に影響を与えることができます。実際には、高G＆Bは、画像の上に、明るく、最終的には、カメラのセンサーを破損する恐れがあります。これを説明するために、流れの再構築にG＆Bレベルの影響も、この記事で検討されています。前処理工程では、画像は、粒子からの光散乱を強調するために、ハイパスフィルタを用いてフィルタリングされます。画素サイズ、グレースケールを調査体積内の粒子の検出を最大にするように調整されます。 T &quot;&gt;最適化の第三工程は、エピポーラ幾何、カメラパラメータ（焦点距離、主点、及び歪み係数）、および屈折率の変化に基づいて立体視画像化の正確なキャリブレーションである。このプロセスは、3Dを最小にするために不可欠です基準目標点の再構成エラー。エピポーラ幾何学は、対象画像からと傾斜角度（カメラと呼び掛けボリュームとの間の）相対距離を使用しています。調査体積を介してカメラビューに沿って屈折率の変化は質量の手順に基づいて考慮することができますら 21は、この実験では、規則的に分布ターゲットポイントと3D階段状構造は、標的として使用されます。 2つだけの画像が3次元粒子位置を決定するために必要とされるが、3D-PTV実験では、通常、複数のカメラを曖昧21を減少させるために使用されます。複数のハイスピー​​ドカメラで高価なセットアップする代わりに、viのですEWの3D-PTVの使用についてホイヤーらによって提案されたスプリッタ、35、最近の生物医学的用途のためにGulean ら 28によって適用されます。ビュースプリッタは、ピラミッド型のミラー（ここに至って主鏡）と4つの調整可能なミラー（副鏡ここに至って）で構成されています。この研究では、4つのビュースプリッタと単一のカメラが4台のカメラからの立体画像化を模倣するために使用しました。システムは、直径、dは H = 1 cmで再 ≈7,000ラグランジアンからとパイプジェットの中間流れ場を特徴付けるために使用され、オイラーは、ジェット原点から下流の周りに14.5から18.5の直径でフレーム。

<table><tbody><tr><td>Mikrotron 4CXP 4 lanes CXP-6 CoaXPress</td><td>ImageOps</td><td>CAMMC4082</td><td>High-speed camera</td></tr><tr><td>Active Silicon FireBird CoaX Frame Grabber</td><td>ImageOps</td><td>FBD-4XCXP6</td><td>Frame Grabber</td></tr><tr><td>100 &amp;mu;m silver-coated hollow ceramic spheres</td><td>Potters Industries LLC</td><td>AG-SL150-30-TRD</td><td>Seeding Paritcles</td></tr><tr><td>StreamPix6</td><td>Upstate Technical Equipment CO.,INC</td><td>MISNOR-STP-6-S-CL</td><td>Camera appliation</td></tr><tr><td>Four-view splitter</td><td>Photrack AG</td><td></td><td>Customized part and necessary if performing 3D-PTV with one camera</td></tr><tr><td>250 Watts Spotlight Halogen</td><td>General Electrics</td><td>23719</td><td>Light source</td></tr><tr><td>OpenPTV (Software)</td><td>OpenPTV (http://www.openptv.net)</td><td></td><td>Open source particle tracking software (Note: available as a service for anyone who wants to use it without all the installation mess or computer power availability problems).</td></tr></tbody></table>

three-dimensional particle tracking velocimetry for turbulence applications: case of a jet flow

3D-PTVは、画像シーケンスの立体記録を用いて、三次元での粒子の組のラグランジュ経路を追跡することを目的と定量流量測定技術です。 4ビュースプリッタと高速度カメラからなる3D-PTVトポロジの基本的なコンポーネント、機能、制約および最適化のヒントは、この資料に記載され議論されています。技術は、 再 ≈7,000に円形噴流の中間流れ場（5 &lt;X / D &lt;25）に適用されます。オイラーフレーム内のラグランジュフロー機能や乱流の量はジェット起源の下流10の直径の周りに、ジェットコアからの様々な半径方向距離であると推定されています。ラグランジュのプロパティは軌道、選択された粒子の速度と加速度だけでなく、Frenet-Serret方程式から得られる流路の曲率を含みます。 10に位置するクロスプレーンでのジェットコア軸周りの3D速度と乱流場の推定ジェットの下流の直径は、文献と比較して、大規模な流れ方向速度運動のパワースペクトルは、ジェットコアから様々な半径方向距離で得られます。

写真とセットアップの概略図は、 図 1及び2に示されています。較正ターゲットは、基準マークは、 図 3に示されている図スプリッタおよび3Dキャリブレーションの再構成に反映しました。認識されたキャリブレーションターゲットのRMSは、流れ方向のx、スパン方向y及び深さz方向に7.3ミクロン、5.7ミクロ...

Watch this Scientific Journal Video about Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow at JoVE.com

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

四ビュースプリッターと高速度カメラに基づいた三次元粒子追跡速度測定（3D-PTV）システムは、ここに記載されています。技術は、下流≈7,000レイノルズ数Reで10直径の近傍に円管からの噴流に適用されます。

ジェット流の場合：乱流のアプリケーションのための3次元粒子追跡流速

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic ...

three-dimensional-particle-tracking-velocimetry-for-turbulence

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12.1K ビュー.  University of Illinois at Urbana-Champaign. 四ビュースプリッターと高速度カメラに基づいた三次元粒子追跡速度測定（3D-PTV）システムは、ここに記載されています。技術は、下流≈7,000レイノルズ数Reで10直径の近傍に円管からの噴流に適用されます。 

ビデオ: Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

Determining 3D Flow Fields via Multi-camera Light Field Imaging

In the field of fluid mechanics, the resolution of computational schemes has outpaced experimental methods and widened the gap between predicted and observed phenomena in fluid flows. Thus, a need exists for an accessible method capable of resolving three-dimensional (3D) data sets for a range of problems. We present a novel technique for performing quantitative 3D imaging of many types of flow fields. The 3D technique enables investigation of complicated velocity fields and bubbly flows. Measurements of these types present a variety of challenges to the instrument. For instance, optically dense bubbly multiphase flows cannot be readily imaged by traditional, non-invasive flow measurement techniques due to the bubbles occluding optical access to the interior regions of the volume of interest. By using Light Field Imaging we are able to reparameterize images captured by an array of cameras to reconstruct a 3D volumetric map for every time instance, despite partial occlusions in the volume. The technique makes use of an algorithm known as synthetic aperture (SA) refocusing, whereby a 3D focal stack is generated by combining images from several cameras post-capture 1. Light Field Imaging allows for the capture of angular as well as spatial information about the light rays, and hence enables 3D scene reconstruction. Quantitative information can then be extracted from the 3D reconstructions using a variety of processing algorithms. In particular, we have developed measurement methods based on Light Field Imaging for performing 3D particle image velocimetry (PIV), extracting bubbles in a 3D field and tracking the boundary of a flickering flame. We present the fundamentals of the Light Field Imaging methodology in the context of our setup for performing 3DPIV of the airflow passing over a set of synthetic vocal folds, and show representative results from application of the technique to a bubble-entraining plunging jet.

A technique for performing quantitative three-dimensional (3D) imaging for a range of fluid flows is presented. Using concepts from the area of Light Field Imaging, we reconstruct 3D volumes from arrays of images. Our 3D results span a broad range including velocity fields and multi-phase bubble size distributions.

マルチカメラライトフィールドイメージングを介して3D流れ場の決定

In the field of fluid mechanics, the resolution of computational schemes has outpaced experimental methods and widened the gap between predicted and ...

工学

High-speed Particle Image Velocimetry Near Surfaces

Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The complex nature of these flows may be studied using particle image velocimetry (PIV), a laser-based imaging technique for optically accessible flows. Though many forms of PIV exist that extend the technique beyond the original planar two-component velocity measurement capabilities, the basic PIV system consists of a light source (laser), a camera, tracer particles, and analysis algorithms. The imaging and recording parameters, the light source, and the algorithms are adjusted to optimize the recording for the flow of interest and obtain valid velocity data. 
Common PIV investigations measure two-component velocities in a plane at a few frames per second. However, recent developments in instrumentation have facilitated high-frame rate (&gt; 1 kHz) measurements capable of resolving transient flows with high temporal resolution. Therefore, high-frame rate measurements have enabled investigations on the evolution of the structure and dynamics of highly transient flows. These investigations play a critical role in understanding the fundamental physics of complex flows.
A detailed description for performing high-resolution, high-speed planar PIV to study a transient flow near the surface of a flat plate is presented here. Details for adjusting the parameter constraints such as image and recording properties, the laser sheet properties, and processing algorithms to adapt PIV for any flow of interest are included.

A procedure for studying transient flows near boundaries using high-resolution, high-speed particle image velocimetry (PIV) is described here. PIV is a non-intrusive measurement technique applicable to any optically accessible flow by optimizing several parameter constraints such as the image and recording properties, the laser sheet properties, and analysis algorithms.

表面近くの高速粒子画像流速

Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The ...

Image-based Lagrangian Particle Tracking in Bed-load Experiments

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a relatively low cost. This manuscript describes an application of particle tracking velocimetry (PTV) to a bed-load experiment with lightweight sediment. The key characteristics of the investigated sediment transport conditions were the presence of a covered flow and of a fixed rough bed above which particles were released in limited number at the flume inlet. Under the applied flow conditions, the motion of the individual bed-load particles was intermittent, with alternating movement and stillness terms. The flow pattern was preliminarily characterized by acoustic measurements of vertical profiles of the stream-wise velocity. During process visualization, a large field of view was obtained using two action-cameras placed at different locations along the flume. The experimental protocol is described in terms of channel calibration, experiment realization, image pre-processing, automatic particle tracking, and post-processing of particle track data from the two cameras. The presented proof-of-concept results include probability distributions of the particle hop length and duration. The achievements of this work are compared to those of existing literature to demonstrate the validity of the protocol.

The manuscript presents a protocol for the conduction of bed-load sediment transport experiments where the moving particles are tracked by image analysis. The experimental facility, the procedures for run realization and data processing, and finally some proof-of-concept results are presented here.

ベッド負荷実験における画像ベースのラグランジュ粒子トラッキング

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a ...

環境学

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

乱流で3Dプリント粒子の配向および回転速度を測定するための方法

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

Micro-particle Image Velocimetry for Velocity Profile Measurements of Micro Blood Flows

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows. The images are cross-correlated to give an accurate velocity profile. A protocol is presented for &mu;PIV measurements of blood flows in microchannels. At the scale of the microcirculation, blood cannot be considered a homogeneous fluid, as it is a suspension of flexible particles suspended in plasma, a Newtonian fluid. Shear rate, maximum velocity, velocity profile shape, and flow rate can be derived from these measurements. Several key parameters such as focal depth, particle concentration, and system compliance, are presented in order to ensure accurate, useful data along with examples and representative results for various hematocrits and flow conditions.

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.

マイクロ血流の速度プロファイル測定用マイクロ粒子画像流速

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows. The images are cross-correlated to ...

生物工学

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to turbulent flow conditions are presented. For that purpose, the incipient motion of a single bead is studied on regular substrates that consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic symmetries. The threshold is characterized by the critical Shields number. The criterion for the onset of motion is defined as the displacement from the original equilibrium position to the neighboring one. The displacement and the mode of motion are identified with an imaging system. The laminar flow is induced using a rotational rheometer with a parallel disk configuration. The shear Reynolds number remains below 1. The turbulent flow is induced in a low-speed wind tunnel with open jet test section. The air velocity is regulated with a frequency converter on the blower fan. The velocity profile is measured with a hot wire probe connected to a hot film anemometer. The shear Reynolds number ranges between 40 and 150. The logarithmic velocity law and the modified wall law presented by Rotta are used to infer the shear velocity from the experimental data. The latter is of special interest when the mobile bead is partially exposed to the turbulent flow in the so-called hydraulically transitional flow regime. The shear stress is estimated at onset of motion. Some illustrative results showing the strong impact of the angle of repose, and the exposure of the bead to shear flow are represented in both regimes.

Two different methods for characterizing the incipient particle motion of a single bead as a function of the sediment bed geometry from laminar to turbulent flow are presented.

視覚に基づいた正規の基板の初期粒子の運動特性: 層流乱流の条件から

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to ...

Experimental Investigation of the Flow Structure over a Delta Wing Via Flow Visualization Methods

It is well known that the flow field over a delta wing is dominated by a pair of counter rotating leading edge vortices (LEV). However, their mechanism is not well understood. The flow visualization technique is a promising non-intrusive method to illustrate the complex flow field spatially and temporally. A basic flow visualization setup consists of a high-powered laser and optic lenses to generate the laser sheet, a camera, a tracer particle generator, and a data processor. The wind tunnel setup, the specifications of devices involved, and the corresponding parameter settings are dependent on the flow features to be obtained.
Normal smoke wire flow visualization uses a smoke wire to demonstrate the flow streaklines. However, the performance of this method is limited by poor spatial resolution when it is conducted in a complex flow field. Therefore, an improved smoke flow visualization technique has been developed. This technique illustrates the large-scale global LEV flow field and the small-scale shear layer flow structure at the same time, providing a valuable reference for later detailed particle image velocimetry (PIV) measurement.
In this paper, the application of the improved smoke flow visualization and PIV measurement to study the unsteady flow phenomena over a delta wing is demonstrated. The procedure and cautions for conducting the experiment are listed, including wind tunnel setup, data acquisition, and data processing. The representative results show that these two flow visualization methods are effective techniques for investigating the three-dimensional flow field qualitatively and quantitatively.

Here, we present a protocol to observe unsteady vortical flows over a delta wing using a modified smoke flow visualization technique and investigate the mechanism responsible for the oscillations of the leading-edge vortex breakdown locations.

流れ可視化手法によるデルタ翼上の流れ構造に関する実験的研究

It is well known that the flow field over a delta wing is dominated by a pair of counter rotating leading edge vortices (LEV). However, their mechanism is ...

Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine micro-organisms, and/or sediments in the ocean, or fluidized bed reactors and combustion processes in engineered systems. In order to study the effect of turbulence on the kinematics of particles in such flows, simultaneous measurements of both the flow and particle kinematics are required. Non-intrusive, optical flow measurement techniques for measuring turbulence, or for tracking particles, exist but measuring both simultaneously can be challenging due to interference between the techniques. The method presented herein provides a low cost and relatively simple method to make simultaneous measurements of the flow and particle kinematics. A cross section of the flow is measured using a particle image velocimetry (PIV) technique, which provides two components of velocity in the measurement plane. This technique utilizes a pulsed-laser for illumination of the seeded flow field that is imaged by a digital camera. The particle kinematics are simultaneously imaged using a light emitting diode (LED) line light that illuminates a planar cross section of the flow that overlaps with the PIV field-of-view (FOV). The line light is of low enough power that it does not affect the PIV measurements, but powerful enough to illuminate the larger particles of interest imaged using the high-speed camera. High-speed images that contain the laser pulses from the PIV technique are easily filtered by examining the summed intensity level of each high-speed image. By making the frame rate of the high-speed camera incommensurate with that of the PIV camera frame rate, the number of contaminated frames in the high-speed time series can be minimized. The technique is suitable for mean flows that are predominantly two-dimensional, contain particles that are at least 5 times the mean diameter of the PIV seeding tracers, and are low in concentration.

The technique described herein offers a low cost and relatively simple method to simultaneously measure particle kinematics and turbulence in flows with low particle concentrations. The turbulence is measured using particle image velocimetry (PIV), and particle kinematics are calculated from images obtained with a high-speed camera in an overlapping field-of-view.

フロー イメージング技術を用いた粒子運動と乱流の同時測定

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine ...

Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom

Aortic valve dysfunction and stroke have recently been reported in transcatheter aortic valve implantation (TAVI) patients. Thrombus in the aortic sinus and neo-sinus due to hemodynamic changes has been suspected. In vitro experiments help investigate the hemodynamic characteristics in the cases where an in vivo assessment proves to be limited. In vitro experiments are also more robust, and the variable parameters are controlled readily. Particle image velocimetry (PIV) is a popular velocimetry method for in vitro studies. It provides a high-resolution velocity field such that even small-scale flow features are observed. The purpose of this study is to show how PIV is used to investigate the flow field in the aortic sinus after TAVI. The in vitro setup of the aortic phantom, TAVI for PIV, and the data acquisition process and post-processing flow analysis are described. The hemodynamic parameters are derived, including the velocity, flow stasis, vortex, vorticity, and particle residence. The results confirm that in vitro experiments and PIV help investigate the hemodynamic features in the aortic sinus.

Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom

The present protocol describes particle image velocimetry (PIV) measurements performed to investigate the sinus flow through the in vitro setup of the transcatheter aortic valve (TAV). The hemodynamic parameters based on velocity are also determined.

大動脈ファントム による 血行動態の粒子画像速度測定調査

Aortic valve dysfunction and stroke have recently been reported in transcatheter aortic valve implantation (TAVI) patients. Thrombus in the aortic sinus ...

A Protocol for Real-time 3D Single Particle Tracking

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although various RT-3D-SPT methods have been put forward in recent years, tracking high speed 3D diffusing particles at low photon count rates remains a challenge. Moreover, RT-3D-SPT setups are generally complex and difficult to implement, limiting their widespread application to biological problems. This protocol presents a RT-3D-SPT system named 3D Dynamic Photon Localization Tracking (3D-DyPLoT), which can track particles with high diffusive speed (up to 20 &#181;m2/s) at low photon count rates (down to 10 kHz). 3D-DyPLoT employs a 2D electro-optic deflector (2D-EOD) and a tunable acoustic gradient (TAG) lens to drive a single focused laser spot dynamically in 3D. Combined with an optimized position estimation algorithm, 3D-DyPLoT can lock onto single particles with high tracking speed and high localization precision. Owing to the single excitation and single detection path layout, 3D-DyPLoT is robust and easy to set up. This protocol discusses how to build 3D-DyPLoT step by step. First, the optical layout is described. Next, the system is calibrated and optimized by raster scanning a 190 nm fluorescent bead with the piezoelectric nanopositioner. Finally, to demonstrate real-time 3D tracking ability, 110 nm fluorescent beads are tracked in water.

This protocol details the construction and operation of a real-time 3D single particle tracking microscope capable of tracking nanoscale fluorescent probes at high diffusive speeds and low photon count rates.

リアルタイム 3 D 単一粒子追跡のためのプロトコル

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although ...

ジェット流の場合：乱流のアプリケーションのための3次元粒子追跡流速

要約

さらに動画を探す

この動画の章

マルチカメラライトフィールドイメージングを介して3D流れ場の決定

表面近くの高速粒子画像流速

ベッド負荷実験における画像ベースのラグランジュ粒子トラッキング

乱流で3Dプリント粒子の配向および回転速度を測定するための方法

マイクロ血流の速度プロファイル測定用マイクロ粒子画像流速

視覚に基づいた正規の基板の初期粒子の運動特性: 層流乱流の条件から

流れ可視化手法によるデルタ翼上の流れ構造に関する実験的研究

フローイメージング技術を用いた粒子運動と乱流の同時測定

大動脈ファントムによる血行動態の粒子画像速度測定調査

リアルタイム 3 D 単一粒子追跡のためのプロトコル

ジェット流の場合：乱流のアプリケーションのための3次元粒子追跡流速

要約

さらに動画を探す

この動画の章

マルチカメラライトフィールドイメージングを介して3D流れ場の決定

表面近くの高速粒子画像流速

ベッド負荷実験における画像ベースのラグランジュ粒子トラッキング

乱流で3Dプリント粒子の配向および回転速度を測定するための方法

マイクロ血流の速度プロファイル測定用マイクロ粒子画像流速

視覚に基づいた正規の基板の初期粒子の運動特性: 層流乱流の条件から

流れ可視化手法によるデルタ翼上の流れ構造に関する実験的研究

フロー イメージング技術を用いた粒子運動と乱流の同時測定

大動脈ファントム による 血行動態の粒子画像速度測定調査

リアルタイム 3 D 単一粒子追跡のためのプロトコル

フローイメージング技術を用いた粒子運動と乱流の同時測定

大動脈ファントムによる血行動態の粒子画像速度測定調査