The forced convection (air supply jet) and the natural convection (thermal plume of passenger) co-exist in an aircraft cabin simultaneously. Due to the notable difference of the Reynolds numbers for the two convection processes, the traditional RANS method can hardly simulate the forced/natural convection flows accurately at the same time. In addition, the large geometric ratio between the main air supply inlet and the whole cabin leads to difficulties in grid generation for the cabin space. An efficient computational model based on the standard k-e model is established to solve these problems. The coefficients in the dissipative equation are modified to compensate the enlarged numerical dissipation caused by coarse grid; meanwhile, the piecewise-defined turbulent viscosity is introduced to combine the forced and natural convection. The modified model is validated by available experimental results in a Boeing 737-200 mock-up. Furthermore, the unsteady characteristic of the aircraft cabin environment is obtained and analyzed. According to the frequency analysis, it turns out that the thermal plume is the main factor of the unsteady fluctuation in cabin.

中文翻译：

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一种改进的湍流模型，用于模拟具有混合对流的气流飞机客舱环境。

强制对流（供气喷射）和自然对流（乘客热羽流）同时存在于机舱内。由于两种对流过程的雷诺数存在显着差异，传统的RANS方法很难同时准确模拟强制/自然对流流动。此外，主送风口与整个客舱的几何比过大，导致客舱空间网格生成困难。建立基于标准ke模型的高效计算模型来解决这些问题。修正了耗散方程中的系数，以补偿粗网格造成的放大的数值耗散；同时，引入分段定义的湍流粘度，将强制对流和自然对流结合起来。修改后的模型已通过波音 737-200 模型中的可用实验结果进行验证。进而获得并分析了机舱环境的非定常特性。频率分析表明，热羽流是舱内非定常波动的主要因素。