侧加热腔体内重力波演化过程的数值模拟

NUMERICAL SIMULATION OF THE FORMATION AND DEVELOPMENT OF INTERNAL GRAVITY WAVE IN A DIFFERENTIALLY HEATED CAVITY

  • 摘要: 利用二维数值模拟的方法研究了侧加热腔体内的自然对流. 基于数值模拟结果,描述了水平热入侵流(intrusion)的整个演化过程,并对该过程的物理机制进行了讨论. 结果表明:当热入侵流抵达腔体冷壁后,由于冷壁无法卷入所有的热入侵流,热入侵流在冷上角堆积并产生一个反向流动,在冷壁边界层附近形成一个顺时针涡,该涡在浮力效应驱动下可返回热壁,并在腔体的冷热壁之间形成了腔体尺度的流体振荡,即内重力波.

     

    Abstract: A two dimensional numerical simulation ofnatural convection in a differentially heated cavity is performed. Theevolution of the horizontal hot intrusion is observed and its physicalproperties are described. The numerical results show that, after the hotintrusion reaches the cold wall, some accumulates in the cold top corner,since the cold boundary layer flow cannotentrain all of the hot intrusion. Due to the hot fluid accumulation and the buoyancyeffect, a reverse flow (opposing the cold boundary layer flow) first arisesin the cold top corner, and then forms a clockwise local circulation. Thiscirculation may move back to the hot wall, and ultimately a cavity-scaleoscillation (i.e. internal gravity wave) is resulted between the hot and coldwalls underneath the ceiling of the cavity. Such oscillation significantlydecays with the passage of time, and almost disappears after twoperiods.

     

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