Decomposition of the wall-heat flux of compressible boundary layers
Decomposition of the wall-heat flux of compressible boundary layers
复制标题
DOI：
10.1063/5.0150696
复制
发表时间：
2023-06
影响因子：
4.6
通讯作者：
P. Ricco;L. Duan
中科院分区：
文献类型：
--
作者：
P. Ricco;L. Duan
我们使用Elnahhas和约翰逊开发的方法[“湍流增强边界层表面摩擦：角动量方法，”J. Fluid Mech.940，A36（2022）]和Xu等人[“可压缩边界层的表面摩擦系数的分解，”Phys. Fluids 35，035107（2023）]的方法，对高雷诺数可压缩边界层的平均温度方程进行积分，得到壁面热流分解的恒等式。物理解释的身份和这种方法的局限性进行了讨论。我们执行的平均温度方程的积分，以获得一个身份，这是传热模拟的可压缩冯卡门动量积分方程的皮肤摩擦系数。这个身份适用于层流和湍流可压缩边界层的数值数据，揭示了平均流耗散和生产的湍流动能所给出的Favre雷诺应力占主导地位的热能平衡。与湍流边界层增长有关的项与壁面冷却相反。受Reynolds等人[“Contribution of Reynolds stress distribution to the skin friction in wall-bounded flows，”Phys. Fluids 14（11），L73-L76（2002）]方法启发，对壁面热通量的其他恒等式进行了数值研究和渐近方法研究。这些恒等式的项虚假地依赖于积分上界，因为这个上界是在推导中使用的数学量。当边界渐近大时，积分恒等式简化为冯·卡门动量方程的热传导模拟。我们还证明了一个现有的多重积分恒等式减少到壁热流的定义时，积分的数量是渐近大。由于积分数的影响是非物理的，因此没有提取关于壁面传热的信息。
We use the method developed by Elnahhas and Johnson [“On the enhancement of boundary layer skin friction by turbulence: An angular momentum approach,” J. Fluid Mech. 940, A36 (2022)] and Xu et al. [“Decomposition of the skin-friction coefficient of compressible boundary layers,” Phys. Fluids 35, 035107 (2023)] for the decomposition of the skin-friction coefficient to integrate the mean temperature equation for high-Reynolds-number compressible boundary layers and arrive at an identity for the decomposition of the wall-heat flux. The physical interpretation of the identity and the limitations of this approach are discussed. We perform an integration on the mean temperature equation to obtain an identity that is the heat-transfer analog to the compressible von Kármán momentum integral equation for the skin-friction coefficient. This identity is applied to numerical data for laminar and turbulent compressible boundary layers, revealing that the mean-flow dissipation and production of turbulent kinetic energy given by the Favre–Reynolds stresses dominate the thermal-energy balance. The term related to the growth of the turbulent boundary layer opposes the wall cooling. Other identities for the wall-heat flux, inspired by the method of Fukagata et al. [“Contribution of Reynolds stress distribution to the skin friction in wall-bounded flows,” Phys. Fluids 14(11), L73–L76 (2002)], are studied numerically and by asymptotic methods. The terms of these identities depend spuriously on the upper integration bound because this bound is a mathematical quantity used in the derivation. When the bound is asymptotically large, the integral identities simplify to the heat-transfer analog to the von Kármán momentum equation. We also prove that an existing multiple-integration identity reduces to the definition of the wall-heat flux when the number of integrations is asymptotically large. No information about the wall-heat transfer is extracted because the impact of the integration number is nonphysical.