CAJ | 학술논문

采用大涡模拟对低雷诺数槽道湍流进行了数值模拟,进口边界条件采用了给定扰动波方法,经过短过渡段得到完全发展湍流.计算中采用了动态亚格子模型和预处理技术,进口采用的动量厚度雷诺数是670.大涡模拟对计算得到的平均速度剖面以及脉动分量与DNS解进行对比,验证了计算结果的可靠性.计算结果显示了湍流场中马蹄涡的形成及演化过程,其中包括形成单腿马蹄涡和形成对称涡腿的马蹄涡,同时发现流场中存在由亚谐波引起的拟序结构的交错现象,并在此基础上分析了湍流边界层近壁区马蹄涡结构的演化.
채용대와모의대저뢰낙수조도단류진행료수치모의,진구변계조건채용료급정우동파방법,경과단과도단득도완전발전단류.계산중채용료동태아격자모형화예처리기술,진구채용적동량후도뢰낙수시670.대와모의대계산득도적평균속도부면이급맥동분량여DNS해진행대비,험증료계산결과적가고성.계산결과현시료단류장중마제와적형성급연화과정,기중포괄형성단퇴마제와화형성대칭와퇴적마제와,동시발현류장중존재유아해파인기적의서결구적교착현상,병재차기출상분석료단류변계층근벽구마제와결구적연화.
The low-Reynolds-number full developed turbulent flow in channels is simulated using large eddy simulation (LES) method with the preconditioned algorithm and the dynamic subgrid-scale model, with a given disturbance in inlet boundary, after a short development section. The inlet Reynolds number based on momentum thickness is 670. The computed results show good agreement with direct numerical simulation (DNS), which include root mean square fluctuated velocity distribution and average velocity distribution. It is also found that the staggered phenomenon of the coherent structures is caused by sub-harmonic. The results clearly show the formation and evolution of horseshoe vortex in the turbulent boundary layer, including horseshoe vortex structure with a pair of streamwise vortexes and one-side leg of horseshoe vortex. Based on the results, the development of the horseshoe-shaped coherent structures is analyzed in turbulent boundary layer.