北京大学 工学院, 湍流与复杂系统国家重点实验室,北京,100871
荀伟康(1999—),男,山西晋中人,博士研究生,研究方向:湍流. E-mail:2301111697@stu.pku.edu.cn
杨延涛*,长聘副教授,研究方向:湍流、计算流体力学. E-mail:yantao.yang@pku.edu.cn
纸质出版:2025
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荀伟康, 杨延涛. 带水平剪切的温盐稳定分层流动数值模拟[J]. 空气动力学学报, 2025, 43(6): 120−130.
XUN Weikang, YANG Yantao. Numerical simulation of the stably stratified thermohaline flow with horizontal shear[J]. 2025, 43(6): 120-130.
荀伟康, 杨延涛. 带水平剪切的温盐稳定分层流动数值模拟[J]. 空气动力学学报, 2025, 43(6): 120−130. DOI: 10.7638/kqdlxxb-2025.0007
XUN Weikang, YANG Yantao. Numerical simulation of the stably stratified thermohaline flow with horizontal shear[J]. 2025, 43(6): 120-130. DOI: 10.7638/kqdlxxb-2025.0007.
海洋中普遍存在由温度、盐度差异形成的垂向密度分层现象,其典型流动结构包括对流混合层和强密度梯度层。为研究这种分层结构对温度、盐度和密度垂向混合输运的影响规律,针对由致稳温度梯度和盐度梯度组成的双分层流体,提出了一种在背景剪切作用下由有限大小初始扰动诱发的非线性分层形成机制,并利用二维直接数值模拟验证了该机制能够诱发分层流态。结果表明:温度剪切强度直接影响密度分层界面的光滑程度;平均密度剖面的分层形态主要由平均盐度剖面形态主导;流场瞬时热流和盐流具有强相关性,表明二者对流输运均由流场中高密度梯度界面的空间振荡运动主导。本研究揭示了海洋温盐湍流混合的一种新形态,对发展海洋温盐分层湍流的参数化模型具有重要参考价值。
Vertical density stratification commonly observed in the ocean due to temperature and salinity variations. Its typical flow structures include convective mixed layers and sharp density gradient layers. To investigate the influence of such stratification on the vertical mixing and transport of temperature
salinity
and density
this paper proposes a nonlinear stratification formation mechanism induced by finite-amplitude initial perturbations in doubly stratified fluids (comprising stabilizing temperature and salinity gradients) under background shear. Two-dimensional direct numerical simulation mothod were used to validate this mechanism can induce the layered flow structure. The result shows that: (1) The strength of the temperature shear directly affects the smoothness of the density interface; (2) The morphology of the mean density profile is primarily dominated by the shape of the mean salinity profile; (3) The instantaneous heat flux and salt flux within the flow field exhibit strong correlation
indicating that their convective transport is both dominated by the spatial oscillatory motion of the high-density-gradient interface. This research reveals a new mixing mechanism in oceanic thermohaline turbulence
providing valuable insights for developing parameterization models of thermohaline stratified turbulence in the ocean.
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