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基于RANS_LES混合方法的分离流动模拟研究

陈浩1,袁先旭1,毕林1,华如豪2,司芳芳1,唐志共1,3   

  1. 1. 中国空气动力研究与发展中心
    2. 西北工业大学
    3.
  • 收稿日期:2019-11-06 修回日期:2020-03-25 出版日期:2020-04-03 发布日期:2020-04-03
  • 通讯作者: 陈浩
  • 基金资助:
    国家数值风洞工程;空气动力学国家重点实验室研究基金

Simulation of separated flow based on RANS/LES hybrid method

  • Received:2019-11-06 Revised:2020-03-25 Online:2020-04-03 Published:2020-04-03
  • Contact: Hao CHEN

摘要: 飞行器在大攻角、快速俯仰机动时,流场中含有大尺度、非定常的涡结构,传统RANS模型不能准确模拟流场结构,根据国际上相关研究的发展趋势,需要采用混合RANS/LES模型来对复杂分离流动进行准确模拟。本文对基于分区混合与湍流尺度混合的双重RANS/LES混合计算模型进一步发展与应用。通过典型简化模型的静、动态湍流大分离流动,测试和验证所采用的DES类方法,重点研究IDDES模型在动态问题应用中的正确性和有效性,并对所采用的数值模拟方法和相应的计算软件的可靠性、鲁棒性以及精度进行了考核验证。典型算例包括超声速圆柱底部流动、跨声速方腔流动、NACA0015机翼深失速分离涡模拟等。计算表明;对于定态非定常分离流动,DES、DDES、IDDES等模型计算结果差别不大,随着流动的非定常特性增强,IDDES模型的优势逐渐显现;对于动态非定常分离流动,则需要采用IDDES类模型。

关键词: 非定常流动, RANS/LES混合模型, 分离流动, IDDES模型

Abstract: When the aircraft is maneuvering at high angle of attack and fast pitch, the flow field contains large-scale and unsteady vor-tices. The traditional RANS model can not accurately simulate the flow field structure. According to the development trend of international research, the hybrid RANS/LES model is needed to accurately simulate the complex separated flow. In this paper, the dual RANS/LES hybrid computational model based on zonal mixing and turbulence scale mixing is further devel-oped and applied. Through the static and dynamic turbulent large separation flow of typical simplified models, DES-based methods are tested and validated. The correctness and validity of IDDES model in the application of dynamic problems are emphatically studied. The reliability, robustness and accuracy of the numerical simulation method and corresponding calcula-tion software are tested and verified. Typical examples include supersonic cylindrical bottom flow, pitch oscillation of NACA0012 airfoil and deep stall separation eddy simulation of NACA0015 airfoil. The requirements of three flow types for turbulence simulation methods are given: steady separated flow, static unsteady separated flow and dynamic unsteady sepa-rated flow. The results show that SA and SST models can give ideal results for static separated flows, DES, DDES and IDDES models are equivalent for static unsteady separated flows, and IDDES models are needed for dynamic unsteady separated flows.

Key words: unsteady flow, the hybrid RANS/LES model, separated flow, IDDES model

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