Extended integral wall-model for large-eddy simulations of compressible wall-bounded turbulent flows

Boussuge, Jean‐François; Catchirayer, Mathieu; Sagaut, Pierre; Montagnac, Marc; Garnaud, Xavier; Papadogiannis, Dimitrios

doi:10.1063/1.5030859

Cited by 32 publications

(13 citation statements)

References 87 publications

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“…Nonequilibrium wall models that do not need PDE solvers for the full RANS equations would be advantageous as they would not need to deal with accounting for the resolved Reynolds stresses and would not need additional grid generation. There are a few other wall models, like the integral wall model by Yang et al [85] and its compressible extension (Catchirayer et al [15]) which try to account for some of the non-equilibrium terms using a set of parameterized velocity and temperature profiles. The wall model by Komives et al [45] tries to incorporate some of the non-equilibrium effects by adding source terms from the LES in combination with the SA-RANS turbulence model.…”

Section: Wall-stress Modeling Methodsmentioning

confidence: 99%

Wall modeled LES of compressible flows at non-equilibrium conditions

Mettu

Subbareddy

2018

2018 Fluid Dynamics Conference

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METTU, BALACHANDRA REDDY. Wall Modeled LES of Compressible Flows in Non-Equilibrium Conditions. (Under the direction of Pramod Subbareddy.)A turbulent boundary layer is composed of a wide range of length scales and time scales. To resolve all these scales of motion, as with a DNS or traditional wall resolved LES, the grid sizes required scale roughly as the square/cube of the Reynolds number (Re). These requirements make high Re flows computationally very expensive. By modeling the effect of the motions close to the wall, as is proposed in wall modeled LES (WMLES) methods, the computation of high Re flows can be made significantly cheaper. To date, WMLES has been relatively less studied in application with strong compressibility effects.In this study, we implement state-of-the-art wall models for these flows and examine the different challenges which are common to high-speed flow applications: isothermal cold wall conditions, the transition to turbulence, and shock boundary layer interactions (SBLI). It is observed that for cold-wall flows, a more empirical "mixed" scaling for the length scale appearing in the eddy viscosity formulation outperforms the classical semi-local scaling for obtaining predictions of heat-flux and skin-friction. For transitional flows, we develop a modified transition sensor that gave robust predictions for the high Mach number cases we examined. We find that the more computationally expensive non-equilibrium model with an eddy viscosity formulation based on the pressure gradient outperformed the standard equilibrium model for skin-friction predictions in SBLIs. A sensor for detecting regions of non-equilibrium flow was developed based on the resolved Reynolds stress. By using this sensor and switching to an exchange location closer to the wall in the non-equilibrium region for the equilibrium model gave skin-friction and heat flux results close to or even better than the non-equilibrium model at a far cheaper cost. WMLES was performed for SBLI at moderate to high Re with different wall temperature conditions. It was observed that WMLES was able to capture the expansion and shrinking of the separation bubble size when the wall was heated and cooled. Also observed was that using WMLES the low-frequency characteristics of SBLI at high Re was now possible. As a whole, it was seen that WMLES can become a promising tool for exploring the complex physics involved in turbulent high-speed flows at a significantly lower cost than wall resolved LES/DNS and with much higher fidelity compared to pure RANS simulations.

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Section: Wall-stress Modeling Methodsmentioning

confidence: 99%

Wall modeled LES of compressible flows at non-equilibrium conditions

Mettu

Subbareddy

2018

2018 Fluid Dynamics Conference

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“…Improvements have been proposed, to take into account non-equilibrium effects (Kawai and Larsson [39] , Park and Moin [49] ), or a pressure gradient (Afzal [2] , Duprat et al [21] ). Wall-modeling for LES is still to this day an on-going research topic (Yang et al [76,77] , Catchirayer et al [12] , Bae et al [9] ), reviews of wall-modeled LES may be found in Piomelli and Balaras [53] , Piomelli [52] , Larsson et al [41] , Bose and Park [11] . Similar to RANS/LES or DES approaches, wall-modeling techniques have enabled a growing literature devoted to turbomachinery LES, as detailed in reviews by Flohr and HÃl [23] , Dufour et al [20] , Sagaut [57] , Gourdain et al [33] , Tucker et al [68][69][70] .…”

Section: Introductionmentioning

confidence: 99%

A mesh adaptation strategy for complex wall-modeled turbomachinery LES

et al. 2021

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A mesh adaptation methodology for wall-modeled turbomachinery Large Eddy Simulation (LES) is proposed, simultaneously taking into account two quantities of interest: the average kinetic energy dissipation rate and the normalized wall distance y + . This strategy is first tested on a highly loaded transonic blade with separated flow, and is compared to wall-resolved LES results, as well as experimental data. The adaptation methodology allows to predict fairly well the boundary layer transition on the suction side and the recirculation bubble of the pressure side. The method is then tested on a real turbofan stage for which it is shown that the general operating point of the computation converges toward the experimental one. Furthermore, comparison of turbulence predictions with hot-wire anemometry show good agreement as soon as a first adaptation is performed, which confirms the efficiency of the proposed adaptation method.

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“…On the other hand, the PDE Integral wall model with its already proven cost-effectiveness over differentialcomplexity models, is approached in this study from the perspective of the strategy and the challenges associated with its implementation in an unstructured-grid cell-centered finite-volume LES solver. It should be noted that the original formulation of this model by Yang et al [13] was implemented in a structured-grid finite-difference/spectral solver, and a later extension of the model to the compressible flows by Catchirayer et al [16] employed a finite-volume structured-grid solver. This makes the present study the first effort in the extension of this method to more versatile unstructured-grid, finite-volume LES solvers, which are frequently and preferably used in the industry and the research community alike, due to their ability to handle complex geometries.…”

Section: Introductionmentioning

confidence: 99%

Implementation and performance analysis of efficient grid-free integral wall models in unstructured-grid LES solvers

Hayat¹,

Park²

2021

Preprint

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Two zonal wall-models based on integral form of the boundary layer differential equations, albeit with algebraic complexity, have been implemented in an unstructured-grid cell-centered finite-volume LES solver.The first model is a novel implementation of the ODE equilibrium wall model where the velocity profile is expressed in the integral form using the constant shear-stress layer assumption and the integral is evaluated using a spectral quadrature method, resulting in a local and algebraic (grid-free) formulation. The second model, which closely follows the integral wall model of Yang et al. (Phys. Fluids 27, 025112 (2015)), is based on the vertically-integrated thin-boundary-layer PDE along with a prescribed composite velocity profile in the wall-modeled region. The prescribed profile allows for a grid-free analytical integration of the PDE in the wall-normal direction, rendering this model algebraic in space. Several numerical challenges unique to the implementation of these integral models in unstructured mesh environments are identified and possible remedies are proposed. The performance of the wall models is also assessed against the traditional finite-volume based ODE Equilibrium wall model.

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Extended integral wall-model for large-eddy simulations of compressible wall-bounded turbulent flows

Cited by 32 publications

References 87 publications

Wall modeled LES of compressible flows at non-equilibrium conditions

Wall modeled LES of compressible flows at non-equilibrium conditions

A mesh adaptation strategy for complex wall-modeled turbomachinery LES

Implementation and performance analysis of efficient grid-free integral wall models in unstructured-grid LES solvers

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