非定常求解的内迭代初值对计算效率的影响研究

发布时间：2018-03-27 19:07

本文选题：初值外插　切入点：非定常流场求解　出处：《西北工业大学学报》2016年01期

【摘要】：基于非定常流场的双时间求解方法,提出了一种提高非定常流场求解效率的有效策略。通过对前几个时刻的流场信息进行外插来确定下一时刻的迭代初值,使之更接近于收敛解,降低内迭代初始残值,进而提高了非定常流场的求解效率。将流场中每个点的守恒量在时间方向上进行泰勒级数展开,设计了若干种外插格式。采用绕圆柱非定常流动的求解来验证本方法的计算效果,并研究了不同初值外插格式、空间离散格式、时间步长和收敛标准对初值外插方法效果的影响。研究表明,在双时间步法基础上,采用初值外插策略可普遍提高计算效率,其中交替外插策略可以普遍将求解效率提高1倍左右。相比于迎风格式,该方法对中心格式的求解效率提高更显著,并且对于不同的收敛标准和时间步数均有非常明显的效果。
[Abstract]:Based on the two-time solution method of unsteady flow field, an effective strategy to improve the efficiency of solving unsteady flow field is proposed. The initial iteration value of the next moment is determined by extrapolating the flow field information of the previous time. By making it closer to the convergence solution and reducing the initial residual value of the internal iteration, the efficiency of solving the unsteady flow field is improved. The Taylor series expansion of the conserved quantity of each point in the flow field is carried out in the time direction. Several extrapolation schemes are designed. The solution of unsteady flow around a cylinder is used to verify the results of this method, and the different initial extrapolation schemes, spatial discrete schemes, are studied. The effect of time step size and convergence criterion on the effect of initial value extrapolation method is studied. It is shown that based on the dual time step method, the calculation efficiency can be generally improved by using the initial value extrapolation strategy. The alternative extrapolation strategy can generally increase the efficiency of the solution by about twice as much as that of the upwind scheme. Compared with the upwind scheme, the method can improve the efficiency of the central scheme more significantly, and has a very obvious effect on the different convergence criteria and the number of time steps.
【作者单位】：西北工业大学航空学院;
【分类号】：O35

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