Interdisciplinary approach to high Reynolds number turbulence

(1) theory将统计湍流理论中的多点波动相关方程分离为单点方程，从而适用于实际关注的湍流。得到了不可压缩混合层和湍流预混火焰的孤立波解。紊流强度、雷诺应力和紊流火焰速度均由该解求得，无需任何经验常数，与已有实验结果吻合良好（Tsuge）。讨论了具有自由表面和对流速度的波的绝对不稳定性和对流不稳定性。利用Floquet定理（Kyotoh）得到了空间周期流的稳定性极限。(2)采用涡旋法（不可压缩）和有限体积法（可压缩）处理cfd高雷诺数混合层。讨论了压缩性的影响和一种新的湍流边界层主动控制装置（Inoue）。采用二维薄层Navier-Stokes形式对壁面反射激波引起的非定常热场进行了数值预测。对代数RNG模型进行了改进，使其适用于Garabedian-Korn剖面，结果与Baldwin-Lomax模型（Nakamura）吻合良好。在计算机翼下倾旋涡脱落时，有必要将非平衡效应纳入湍流建模（Fujii）。脉冲射流燃烧的分析表明，由于斜压与火焰本身产生的压缩波的相互作用，火焰表面产生了相当大的畸变（Hayashi）。提出了一种三阶多向迎风有限差分格式。应用于复杂几何形状的高雷诺数非定常流场，精度令人满意（Kuwahara）。(3)实验：确定了强剪切和火焰拉伸作用下的保火机理（Niioka）。研究了平面/凹板边界层的过渡，发现纵向涡旋与外层湍流点（平板）之间存在反馈系统，并且存在三种湍流模式（Gortler涡旋）（Aihara）。开发了一种四次跟踪装置，通过控制图像处理中的频闪发射到6msec来实现计算流速的算法（Nishikawa）。通过对热逆流射流的激光多普勒测量，澄清了超流体He向湍流和T_1-T_2跃迁的证据（Murakami）。混合层中相干结构的初始阶段在很长的流向范围内持续存在（Suzuki）。研制了高分辨率测量装置，并将其应用于湍流凝胶中CO_2浓度（瑞利散射）和火焰中OH荧光（LIF）的测量。研究了湍流边界层与尖/钝鳍产生的三维激波以及弓形激波的相互作用。观察到边界层以几kHz（Asou）的频率重复二次分离/附着。少

(1)THEORYMulti-point fluctuation-correlation equations of the statistical turbulence theory are separated into single-point equations, thereby made applicable to turbulent flows of practical interest. The solitary-wave solution of the equation is obtained for incompressible mixing layrs and turbulent premixed flames. Turbulence intensity, Reynolds' stress and turbulent flame speed are obtained from this solution without having recourse to any empirical constants, and in good agreement with existing experiments(Tsuge). Absolute and convective instabilities of waves with free surface and convection velocity are discussed. Stability limit of spatially periodic flow is obtained using the Floquet theorem(Kyotoh).(2)CFDHigh Reynolds number mixing layr is dealt with using vortex method(incompressible) and finite volume method (compressible). Effects due to compressivility and a novel active control device of turbulent boundary layr are discussed(Inoue). Mumerical prediction of unsteady heatin … More g caused by wall-reflected shock waves is made using 2-D thin layr Navier-Stokes formalism(Asou). Algebraic RNG model is improved to make it applicable to Garabedian-Korn profile and the result shows good agreement with Baldwin-Lomax model(Nakamura). It is necessary to incorporate nonequilibrium effect on turbulence modeling in computing vortex shedding in the nose-down posture of a wing(Fujii). Analysis of pulse jet combution shows considerable distortion of the flame surface due to baroclinic interaction with compression waves emerging from flame itself(Hayashi). A method of third order multi-directional upwind finite difference scheme is proposed. It is applied to high Reynolds number unsteady flow with complex geometry with satisfactory accuracy(Kuwahara).(3)EXPERIMENTSMechanism of flame-holding in the presence of strong shear and flame-stretching is identified(Niioka). Transition of flat/concave-plate boundary layrs are investigated, and it is found that there is a feed back system between longitudinal vortices and outer-layr turbulent spots(flat-plate), also that there are three types of turbulence mode(Gortler vortices)(Aihara). A four-time tracking device is developed to materialize algorism to compute flow velocity by controlling stroboscopic emission in the image processing to 6msec(Nishikawa). Evidence of transition to turbulence and T_1-T_2 transition in super-fluid He is clarified through the laser-doppler measurement of thermal counter flow jets(Murakami). Initial stage of coherent structure in the mixing layr is shown to persist over a long streamwise range(Suzuki). High resolution measurement devise is developed and is applied to measuring CO_2 concentration in turbulent jel(Rayleigh scattering)and OH fluorescence in flames(LIF)(YOSHIKAWA). Interactions of utrbulent boundary layr with 3-D shock waves generated by sharp/blunt fins also with bow shock waves are investigated. It is observed that the boundary layr repeats secondary detach/attach-ment with frequencies of several kHz(Asou). Less