Proof of Concept in Pressure Correlation Measurement in Turbulent Flows (Expedited Award for Novel Research)

由于控制参数的时空涨落的相互作用，湍流预混火焰中的应力和标量的传输很难预测。建立动力学模型需要消除运动方程中的麻烦项。一组难以捉摸的参数涉及到压力-速度波动。这项研究将集中在一种通过用非侵入式激光方法(多光束、激光多普勒风速测量和瑞利散射)取代侵入式机械麦克风探头来测量等温流中这些波动的技术。压力波动不会直接测量，而是由密度-速度梯度的体积积分计算出来的。拟议的研究涉及等温射流中的压力波动测量。定量结果的重复性和高精度将导致类似的测量在反应射流，将进一步加深我们对湍流的理解，并将增加燃烧模型的科学基础。

The transport of stress and scalar quantities in turbulent premixed flames is difficult to predict because of the interaction between spatial and temporal fluctuations of the controlling parameters. Modeling the dynamics requires elimination of troublesome terms in the equation of motion. One set of elusive parameter involves pressure- velocity fluctuations. The research will focus on a technique to measure these fluctuations in isothermal flows by substituting nonintrusive laser methods (multiple-beam, laser-doppler anemometry and Rayleigh scattering) for intrusive mechanical microphone probes. The pressure fluctuations will not be measured directly but will be calculated from the volume integration of the density-velocity gradients. The proposed research deals with pressure fluctuation measurements in an isothermal jet. Quantitative results which are repeatable and of high accuracy will lead to similar measurements in reacting jets, will further our understanding of turbulence, and will increase the scientific basis for combustion modeling.