Long and Medium-Term Research: Velocity and Concentration Measurements in the Turbulent Jet and the Jet in Counterflow

中长期研究：紊流射流和逆流射流的速度和浓度测量本奖项隶属于国外卓越中心中长期研究项目。它使美国科学家和工程师能够在国外公认的卓越研究中心进行三到十二个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持斯坦福大学的Yoda博士与柏林工业大学的Heinrich Fiedler博士进行为期12个月的博士后研究访问。他们的研究项目包括开发同时获取二维浓度和速度场的技术，用于湍流水流。该技术将首先在轴对称射流这一基本流中发展，以评估其准确性和适用性。然后，他们将使用他们的技术来研究逆流中的射流，这是一种有趣的新流动，因为它显示了从对流到绝对不稳定的转变。在这两种情况下，他们的方法都包括先用荧光染料标记流体以测量二维（被动标量）浓度场，然后用中性浮力粒子来测量速度场，最后用两者的结合来同时获得两个场。这项新技术的结果将阐明对流混合在湍流自由剪切流中的作用。该奖项建议提供资金用于支付国际旅行和12个月的津贴。

Long and Medium-Term Research: Velocity and Concentration Measurements in the Turbulent Jet and the Jet in Counterflow This award is under the Long and Medium-Term Research at Foreign Centers of Excellence Program, which enables U.S. scientists and engineers to conduct three to twelve months of research abroad at research centers of proven excellence. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twelve-month postdoctoral research visit by Dr. Minami Yoda of Stanford to work with Dr. Heinrich Fiedler at the Technical University of Berlin. Their research project involves development of techniques for the simultaneous acquisition of two-dimensional concentration and velocity fields for application in turbulent water flows. This technique will initially be developed in a fundamental flow, the axisymmetric jet, to evaluate its accuracy and applicability. They will then use their technique to investigate the jet in counterflow, a new flow which is of interest because it displays transition from convective to absolute instability. In both cases their approach will involve marking the flows first with flueorescent dye to measure the two-dimensional (passive scalar) concentration field, then with neutrally buoyant particles to measure the velocity field, and finally with a combination of the two to acquire both fields at once. The results from this new technique will clarify the role of convective mixing in turbulent free shear flows. The award recommendation provides funds to cover international travel and a stipend for twelve months.