An improved immersed boundary method for computation of turbulent flows with heat transfer
An improved immersed boundary method for computation of turbulent flows with heat transfer
复制标题
计算传热湍流的改进浸入边界法
DOI：
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发表时间：
2008
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通讯作者：
Seongwon Kang
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作者：
Seongwon Kang
浸入边界法（IB）是一种在数值模拟中对不与网格对齐的表面施加边界条件的方法。这种方法已经被用来作为一种实用的方法来模拟涉及非常复杂的几何形状或运动物体的问题。我们的目标是评估IB方法在湍流流模拟中的准确性和效率，其中近壁区域的流动力学是正确预测整体流的基础。本工作的其余部分着重于基于IB方法的仿真工具的开发，该工具可以正确预测湍流中壁面温度和压力的波动。在第二部分中，我们说明了该方法在多材料传热问题中的应用，其中流体的对流换热和固体的传导换热同时处理。这项工作在浸入边界处获得了较高的精度，并克服了以前的IB方法的缺陷，通过增加额外的约束-与质量守恒的插值速度边界条件相关的兼容性约束和压力的解耦约束。我们推导了一种具有修正边界插值和严格质量守恒格式的IB方法，该方法不显示浸入边界附近的压力振荡。该方法虽然准确，但其复杂性促使了另一种变体-浸入边界近似域法（IB-ADM）的发展。这种方法以较低的计算开销满足压力解耦约束。在几个实例问题中，IB-ADM正确地预测了近壁速度、压力和标量场。结果表明，IB- adm可以成功地预测非常薄的固体物体周围的ow，而以前的IB方法无法获得正确的结果。通过计算湍流通道内的空时压力，成功地验证了IB-ADM的有效性。当应用到紊流流周围的翼型，计算出的低统计-平均/均方根低场和功率谱的壁压力-是在良好的
The immersed boundary (IB) method is a technique to enforce boundary conditions on surfaces not aligned with the mesh in a numerical simulation. This method has been used as a practical approach to model ow problems involving very complex geometries or moving bodies. Our objective is to assess the accuracy and e ciency of the IB method in simulations of turbulent ows, where the ow dynamics in the near-wall region is fundamental to correctly predict the overall ow. The rst part of this work focuses on the development of a simulation tool based on the IB method that can correctly predict the wall temperature and pressure uctuations in turbulent ows. In the second part, we illustrate the application of the method to a multi-material heat transfer problem where convective heat transfer of the uid and conductive heat transfer of the solid are handled simultaneously. This work achieves su cient accuracy at the immersed boundary and overcomes de ciencies in previous IB methods by augmenting the formulation with additional constraints − a compatibility constraint relating the interpolated velocity boundary condition with mass conservation and a decoupling constraint for the pressure. We derived an IB method with a revised boundary interpolation and a strictly mass conserving scheme, which does not show pressure oscillations near the immersed boundary. Although accurate, the complexity of this method prompted the development of another variant − the immersed boundaryapproximated domain method (IB-ADM). This approach satis es the pressure decoupling constraint with an inexpensive computational overhead. The IB-ADM correctly predicts the near-wall velocity, pressure and scalar elds in several example problems. The IB-ADM is shown to successfully predict the ow around a very thin solid object for which incorrect results were obtained with previous IB methods. The IB-ADM has been successfully validated through computation of the wall-pressure space-time correlation in DNS of a turbulent channel ow. When applied to a turbulent ow around an airfoil, the computed ow statistics − the mean/RMS ow eld and power spectra of the wall pressure − are in good