B-C转捩模型的DDES方法模拟转捩大分离流动

DDES for Separated Transitional Flows Based on B-C Transition Model

根据零压力梯度平板的实验数据对B-C转捩模型中的经验关联式进行标定.标定后的B-C转捩模型在进口湍流度较低的平板算例上可以提供更合理的转捩预测结果.但受限于RANS方法自身特性,B-C转捩模型对转捩后出现的大分离流动计算可靠性较差.结合延迟分离涡模拟SA-DDES方法和B-C转捩模型,发展了转捩-延迟分离涡模拟BC-DDES方法.三维S-K平板的数值模拟表明,BC-DDES方法能得到与B-C转捩模型一致的转捩结果.三维圆柱绕流的数值模拟表明,BC-DDES方法得到与实验符合的平均阻力系数和表面压力分布,并且计算花费比tHRLES方法少.

Empirical correlations in B-C transition model were calibrated with experimental values of zero pressure gradient plates.Calibrated B-C transition model predicts reasonably transition positions with low inlet turbulence intensity.However,due to limitations of RANS method,B-C transition model’s accuracy diminishes for massively separated flows.A turbulence closure named transitional Delayed Detached-Eddy Simulation(BC-DDES)method is proposed which combines traditional SA-DDES method and B-C transition model.This method has the potential for accurately capturing massively separated boundary layers in transitional Reynolds number range.Numerical simulation of three-dimensional S-K flat plate shows that BC-DDES method obtains transition prediction consistent with baseline transition model.Comparisons are evaluated on circular cylinder in crossflow.It shows that pressure distribution and drag coefficient of cylinder calculated with BC-DDES method agree well with experimental data,with less computational costs than tHRLES method.