On the generation and maintenance of waves and turbulence in simulations of free-surface turbulence
On the generation and maintenance of waves and turbulence in simulations of free-surface turbulence
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DOI：
10.1016/j.jcp.2009.06.030
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
Xin Guo;Lian Shen
中科院分区：
文献类型：
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作者：
Xin Guo;Lian Shen
波浪与湍流相互作用数值模拟的挑战之一是波浪和湍流场的精确设置和维护。在本文中，我们调查技术的产生和抑制特定的表面波模式，湍流的产生在一个非均匀的物理域与波浪边界拟合网格，和复杂的波-湍流相互作用过程中的波和湍流的产生和维持。我们施加表面压力来产生和抑制波浪。基于线性化Cauchy-Poisson问题的解，推导出三种压力表达式，分别为δ函数法、时间段法和逐步法。数值实验表明，这些方法产生的波符合要求，并能有效地消除杂波。非线性波的影响占与时间松弛方法。对于湍流生成，我们将线性强迫方法扩展到具有曲线计算网格的非均匀物理域。力的分布和计算网格畸变的影响进行了检查。对于波湍流相互作用，我们开发了一种算法来即时识别特定的前进波和驻波。为了精确控制复杂湍流流场中的波动幅度，我们进一步发展了能量控制方法。最后给出了一个波浪与湍流相互作用的数值模拟实例。结果表明，湍流在波浪的存在下具有独特的特征。速度波动被发现是强烈依赖于波的相位，这些波动的变化被解释与波引起的应变场的压力-应变相关性。
One of the challenges in numerical simulation of wave–turbulence interaction is the precise setup and maintenance of wave and turbulence fields. In this paper, we investigate techniques for the generation and suppression of specific surface wave modes, the generation of turbulence in an inhomogeneous physical domain with a wavy boundary-fitted grid, and the generation and maintenance of waves and turbulence during the complex wave–turbulence interaction process. We apply surface pressure to generate and suppress waves. Based on the solution of linearized Cauchy–Poisson problem, we derive three pressure expressions, which lead to a δ-function method, a time-segment method, and a gradual method. Numerical experiments show that these methods generate waves as specified and eliminate spurious waves effectively. The nonlinear wave effect is accounted for with a time-relaxation method. For turbulence generation, we extend the linear forcing method to an inhomogeneous physical domain with a curvilinear computational grid. Effects of force distribution and computational grid distortion are examined. For wave–turbulence interaction, we develop an algorithm to instantaneously identify specific progressive and standing waves. To precisely control the wave amplitude in a complex turbulent flow field, we further develop an energy controlling method. Finally, a simulation example of wave–turbulence interaction is presented. Results show that turbulence has unique features in the presence of waves. Velocity fluctuations are found to be strongly dependent on the wave phase; variations of these fluctuations are explained by the pressure–strain correlation associated with the wave-induced strain field.