The large eddy simulation approach is conducted using the dynamic Smagorinsky model and Favre-averaging method to investigate the flow structure transition and hysteresis phenomenon of mixed convection induced by a transverse buoyant jet, based on the opensource computational fluid dynamics package of the OpenFOAM software. The comparison with the available experimental data proves that this model has good adaptability in reproducing the flow structure and temperature distribution of such a flow field. The results are obtained for Reynolds numbers ranging from 120 to 792, and Rayleigh numbers ranging from $1.8\times 10^9$ to $6.5\times 10^9$. Two types of stable flow structures are observed and systematically studied for different dimensionless parameters, i.e., a clockwise structure dominated by the inertial force, and a counterclockwise structure dominated by the buoyancy force. A hysteresis phenomenon is observed in the flow structure transition, corresponding to the noncoincidence of the first and second transition points. Furtherly, the critical points of transition for different hysteresis curves are highlighted in a Reynolds-number–Rayleigh-number map indicating three flow-regime zones. The transition of flow structure occurs only when the state point moves from the transition zone to another zone across the transition curve.

基于OpenFOAM软件的开源计算流体动力学包，使用动态Smagorinsky模型和Favre平均方法进行大涡模拟方法，研究横向浮力射流引起的混合对流的流动结构转变和滞后现象。与已有实验数据的对比证明，该模型在再现此类流场的流动结构和温度分布方面具有良好的适应性。结果是针对雷诺数范围从 120 到 792 和瑞利数范围从$1.8\times 10^9$ 至 $6.5\times 10^9$. 针对不同的无量纲参数，观察并系统研究了两种类型的稳定流动结构，即以惯性力为主的顺时针结构和以浮力为主的逆时针结构。在流动结构转变中观察到滞后现象，对应于第一和第二转变点的不重合。此外，不同滞后曲线的临界点在雷诺数 - 瑞利数图中突出显示，指示三个流动状态区。只有当状态点从过渡区跨过过渡曲线移动到另一个区时，才会发生流动结构的过渡。