近壁区网格Δy对TTU建筑风场湍流计算的影响  

Influence on Turbulent Flow Calculation of Wind Flow Around TTU Building by Grid Size Δy in Near-Wall Region

作　　者：余志祥[1] 闫雁军[2] 

机构地区：[1]西南交通大学土木工程学院,成都610031 [2]同济大学土木工程学院,上海200092

出　　处：《土木建筑与环境工程》2012年第6期46-51,共6页Journal of Civil,Architectural & Environment Engineering

基　　金：自然科学基金面上项目(90815016);青年科技创新项目(A0920502051208-61)

摘　　要：为了研究近壁区网格厚度Δy对建筑物风场绕流时湍流计算结果的影响,提高k-εEARSM湍流模型用于建筑物数值风洞模拟的准确性,结合TTU试验建筑的实测数据,以Δy为参数进行了数值风洞模拟。对k-εEARSM的雷诺方程进行了解析,并推导了Δy的简化计算公式。基于准稳态时步逼近技术,计算了(y=0.001、0.005、0.01、0.05和0.1m等5种工况下的时均流态,对绕流特征、湍动能分布和中轴线脉动风压系数、平均风压系数进行了比较。研究表明,过小的Δy会导致高湍动区渗透进入近壁区,计算稳定性变差;过大的Δy则会降低高湍动区计算结果的准确性。据此,给出兼顾模拟精度与计算稳定性要求的Δy变化范围为0.01～0.05m;并给出了Δy上限值的经验计算公式。In order to improve the accuracy of simulation in which k-ε EARSM turbulent model was employed, the influence of grids thickness △y on the turbulent variables in flow field around building was researched. Coupled with real data of Texas Tech University experimental building, △y as the main parameter was studied in the numerical wind tunnel simulation. Equation of k-ε EARSM and simplified equation of △y were analyzed and deduced. Quasi-steady State Marching-on-in-time Approximation technology was employed to simulate the average flow in five working conditions, in which y is 0. 001m, 0. 005m, 0. 01m, 0. 05m, and 0. lm, respectively. And based on the results, the comparison of characteristic of flow around building, turbulent kinetic energy coefficient, fluctuating pressure coefficient along axis and mean pressure coefficient was conducted. The results indicate that very small △y will make fluid with high Reynolds number penetrate into near-wall zone, and the calculation stability worsens; on the other side, very large △y will lower simulated accuracy of main variable results in the turbulent region near the cornice with high Reynolds number. Accordingly, △y near the wall ranging from 0.01m-0.05m meets the requirements for accuracy and stability, then the experiential formula of △y upper limit is given.

关 键 词：计算风工程 近壁区网格 湍流计算 k-ε EARSM TTU建筑 

分 类 号：TU398.4[建筑科学—结构工程] TU352.1