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DDES是广泛应用的一类RANS/LES混合方法,其通过引入延迟函数保证近壁区的RANS模化,对分离流动十分有效。目前DDES已发展了多种不同的延迟函数,但对各延迟函数的性能特点认识尚不够充分,尤其缺乏超声速流动中的相关研究。围绕DDES方法中不同延迟函数开展研究工作,选取超声速底部流动作为测试算例,通过与实验数据的系统对比分析,考察不同延迟函数在超声速分离流动中的分布规律、作用效果及模型求解能力。研究表明,不同延迟函数作用范围与求解能力存在差异,其中DDES-F1能够在起到保护作用的同时不损害模型的求解精度,对该流动较为有效,所得结果与实验数据吻合较好。
DDES is a widely used RANS / LES hybrid method, which is very effective in separating flow by introducing RANS modeling in the near wall region by introducing a delay function. At present, DDES has developed a variety of different delay functions, but the understanding of the performance characteristics of each delay function is not enough, especially the lack of relevant research in the supersonic flow. Focusing on the different delay functions in DDES method, supersonic bottom flow is selected as a test case. Through systematic comparison with experimental data, the distribution law, effect and model solving ability of different delay functions in supersonic flow are investigated. The results show that there are differences between the range of action and the solution ability of different delay functions. DDES-F1 can protect the model without impairing the accuracy of the model and is more effective for the flow. The obtained results are in good agreement with the experimental data.