应变耦合一维湍流用于快速畸变
Strain-coupled one-dimensional turbulence for rapid distortion
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中文总结 AI 辅助
本文提出应变耦合一维湍流（ODT）模型，以低成本、一维尺度分辨率演化受应变的湍流，在应变与湍流比约0.8时捕捉到线性理论未体现的非线性涡动力学，重现快速畸变理论并定量匹配雷诺应力各向异性趋势。
中文摘要 AI 辅助
平均应变对湍流的畸变——通过分量放大、压力介导的再分布和谱重标度——是从风洞收缩段到升力面附近滞止区等流动的核心过程。以经济的方式捕捉这一过程仍存在困难：尺度解析模拟成本高昂，线性快速畸变理论忽略了有限应变下的非线性弛豫，而二阶矩封闭则丢弃了谱信息。我们提出了一种应变耦合的一维湍流（ODT）公式，该公式以一维尺度分辨率演化受应变的湍流，且计算成本低。平均应变生成作为线速度的连续强迫施加，快速压力-应变贡献作为与均匀快速畸变理论一致的能量守恒再分布算子引入，尺度压缩则由ODT域的膨胀表示。该模型预测了宽带畸变谱，其在应变与湍流比约为0.8时偏离线性理论的刚性谱平移，此时快速畸变和非线性涡动力学均处于活跃状态。在未受畸变的湍流关于ODT线轴对称的情况下，非局部三维快速压力-应变积分简化为闭合的单线条泛函。该公式在起始阶段重现了快速畸变理论，并定量捕捉了Lee和Reynolds（1985）的雷诺应力各向异性趋势。
英文摘要
The distortion of turbulence by mean strain - through component amplification, pressure-mediated redistribution and spectral rescaling - is central to flows ranging from wind-tunnel contractions to stagnation regions near lifting surfaces. Capturing this process economically remains difficult: scale-resolving simulation is expensive, linear rapid-distortion theory omits nonlinear relaxation over finite strain, and second-moment closures discard spectral information. We present a strain-coupled formulation of one-dimensional turbulence (ODT) that evolves strained turbulence with one-dimensional scale resolution at low computational cost. Mean-strain production is imposed as a continuous forcing of the line velocity, the rapid pressure-strain contribution is introduced as an energy-conserving redistribution operator consistent with homogeneous rapid-distortion theory, and scale compression is represented by dilatation of the ODT domain. The model predicts a broadband distorted spectrum that departs from the rigid spectral translation of linear theory at a strain-to-turbulence ratio of approximately 0.8, where rapid distortion and nonlinear eddy dynamics are both active. Under axisymmetry of the undistorted turbulence about the ODT line, the nonlocal three-dimensional rapid pressure-strain integral reduces to a closed single-line functional. The formulation reproduces rapid-distortion theory at onset and quantitatively captures the Reynolds-stress anisotropy trends of Lee and Reynolds (1985).
