摘要
分离流动是一种复杂湍流现象,其中微小尺度结构的发展演化有着重要的影响,但是湍流数值模拟中数值方法的固有耗散会抑制小尺度流动结构的发展.因此,本文结合延迟分离涡模拟方法,基于五阶耗散紧致格式,通过引入流场相关的调节因子,构造自适应耗散调节方法,使其在大涡模拟区域降低耗散影响以提高对小尺度流动结构的辨识能力,在雷诺平均区域恢复正常耗散水平以保持稳定求解.本文首先通过近似色散关系和涡输运算例说明该方法可有效降低数值耗散影响,同时具有更高分辨率的涡保持能力;随后通过各向同性衰减湍流和平板槽道流动展示了该方法可有效提高对微小流动结构的辨识能力,同时在存在大梯度的流场中可保持求解稳定性;最后求解Re=3900亚临界状态下的圆柱绕流,通过对比流场云图、时均速度和雷诺应力分布曲线,说明了该方法通过减小分离区耗散影响,可有效提高对典型分离流动求解的准确性.
Separate flow is a typical complex turbulent phenomenon.The full development of small-scaled structures is of great importance for accurate numerical simulation.However,these small-scaled structures can be easily damped by the inherent dissipation of numerical method.Therefore,based on the 5th-order dissipative compact scheme(DCS),we propose an adaptive dissipative compact scheme(ADCS),which can adjust the numerical dissipation with self-adaptive capability by incorporating a flow related adjusting parameter.Combining with the delay detached eddy simulation(DDES),the ADCS can reduce the influence of numerical dissipation in LES region to enhance the ability to discern small-scaled structures,and restore the normal dissipation level in the RANS region to keep numerical stability.In the process of numerical simulation,firstly,the approximate dispersion relation(ADR)is obtained,it shows that the ADCS method can effectively reduce the influence of dissipation in the high wave number region,without contaminating the dispersive performance,which is conducive to enhancing the resolution of turbulent structures.Secondly,the advection of vortical structure is simulated.Compared with DCS,the ADCS can reach the theoretical accuracy in an efficient way and acquire more advanced resolution of vortical structure even on a relatively coarse mesh scale,which proves that the ADCS reduces the negative influence of dissipation on vortical structure.The third case is the decay of isotropic turbulence.The energy spectral curves stay close to the reference before cut-off number,showing that more small-scaled structures can be distinguished by the ADCS method,and most of the vortical dominated regions are solved at a near-minimum level.The forth case is the plate channel turbulent flow.Both of DCS method and ADCS method give acceptable results.The ADCS method is performed with optimal dissipation in the near-wall region and reduces the dissipative level in the vortex dominated region,and it is also exhibited that the ADCS method can ma
作者
李昊
刘伟
王圣业
Li Hao;Liu Wei;Wang Sheng-Ye(College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第14期135-149,共15页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11572348)
国防科技大学重大应用基础研究项目(批准号:ZDYYJCYJ20140101)资助的课题.
关键词
分离流动
延迟分离涡模拟
自适应耗散方法
耗散紧致格式
separated flow
delayed-detached eddy simulation
adaptive dissipative method
dissipative compact scheme
