Data assimilation and linear analysis with turbulence modelling: application to airfoil stall flows with PIV measurements

IF 2.2 3区工程技术 Q2 MECHANICS

Theoretical and Computational Fluid Dynamics Pub Date : 2024-06-04 DOI:10.1007/s00162-024-00703-3

Vincent Mons, Arthur Vervynck, Olivier Marquet

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引用次数: 0

Abstract

A combined data-assimilation and linear mean-flow analysis approach is developed to estimate coherent flow fluctuations from limited mean-flow measurements. It also involves Reynolds-Averaged Navier–Stokes (RANS) modelling to efficiently tackle turbulent flows. Considering time-averaged Particle Velocimetry Image (PIV) measurements of the near-stall flow past a NACA0012 airfoil at an angle of attack of \(10^{\circ }\) and in the chord-based Reynolds number range \(4.3 \cdot 10^4 \le Re \le 6.4 \cdot 10^4\), data assimilation is first employed to correct RANS equations that are closed by the Spalart-Allmaras model. The outputs of this procedure are a full mean-flow description that matches the PIV data and a consistent turbulence model that provides not only a mean eddy-viscosity field but also the perturbations of the latter with respect to mean-flow modifications. Global stability and resolvent analyses are then performed based on the so-obtained mean flow and model to satisfactorily predict near-stall low-frequency phenomena, as confirmed through comparison with the Spectral Proper Orthogonal Decomposition (SPOD) of the PIV measurements. This comparison highlights the benefits in taking into account variations in the turbulent eddy-viscosity over a frozen approach for the correct estimation of the present coherent low-frequency oscillations.

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数据同化和线性分析与湍流建模：将 PIV 测量应用于机翼失速流

摘要开发了一种数据同化和线性平均流分析相结合的方法，用于从有限的平均流测量中估算相干流波动。该方法还涉及雷诺平均纳维-斯托克斯（RANS）建模，以有效处理湍流。考虑到在攻角为（10^{circ }\）和基于弦线的雷诺数范围（4.3 \cdot 10^4 \le Re \le 6.4 \cdot 10^4\）内对经过 NACA0012翼面的近失速流进行的时间平均粒子测速图像（PIV）测量，首先采用数据同化来修正由 Spalart-Allmaras 模型封闭的 RANS 方程。这一程序的输出结果是与 PIV 数据相匹配的完整平均流描述和一致的湍流模型，后者不仅提供平均涡-粘度场，还提供平均流修正时的扰动。然后，根据获得的平均流和模型进行全局稳定性和解析分析，以令人满意地预测近滞留低频现象，这一点通过与 PIV 测量的频谱适当正交分解（SPOD）进行比较得到了证实。这种比较凸显了考虑湍流涡粘度变化比采用冻结方法更有利于正确估计目前的相干低频振荡。

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来源期刊

Theoretical and Computational Fluid Dynamics 物理-力学

CiteScore

5.80

自引率

2.90%

发文量

审稿时长

>12 weeks

期刊介绍： Theoretical and Computational Fluid Dynamics provides a forum for the cross fertilization of ideas, tools and techniques across all disciplines in which fluid flow plays a role. The focus is on aspects of fluid dynamics where theory and computation are used to provide insights and data upon which solid physical understanding is revealed. We seek research papers, invited review articles, brief communications, letters and comments addressing flow phenomena of relevance to aeronautical, geophysical, environmental, material, mechanical and life sciences. Papers of a purely algorithmic, experimental or engineering application nature, and papers without significant new physical insights, are outside the scope of this journal. For computational work, authors are responsible for ensuring that any artifacts of discretization and/or implementation are sufficiently controlled such that the numerical results unambiguously support the conclusions drawn. Where appropriate, and to the extent possible, such papers should either include or reference supporting documentation in the form of verification and validation studies.