DNS 1-5
Lib:Flow over a rounded step
Abstract
The HiFi-TURB-DLR rounded step test case is designed to investigate the effect of an adverse pressure gradient on a turbulent boundary layer. The problem considers the flow over a 2D rounded step, see Fig. 1, and is inspired by the axisymmetric rounded step proposed by Disotell and Rumsey [1,2,3].
This test case concerns a highly resolved Direct Numerical Simulation (DNS) using the high-order discontinuous Galerkin (DG) code MIGALE [4]. The code couples the DG space discretization with a high-order implicit time integration, which relies on Rosenbrock schemes.
The primary objective of this contribution is to provide a rich database of flow and turbulence statistics as a reference target for verification and validation of RANS models based subsequent computational campaigns (see UFR 3-35 Test Case).
The provided statistical quantities in the database are:
- mean pressure, density and velocity components;
- Reynolds stress components;
- pressure autocorrelation;
- velocity triple correlation;
- pressure-velocity correlation;
- Taylor microscale;
- Kolmogorov length and time scales;
Notice that the solver discretize the compressible Navier--Stokes equations. Accordingly, density and temperature fields, as well their gradients have been collected during the computational campaign. However, since the flow regime is incompressible (), these fields are not the focus of this contribution and thus are not reported.
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| Figure 1: Rounded step case, Re=78490. Dimensionless instantaneous streamwise velocity at midspan using MIGALE with DG P3 (~300 million DoF/eqn). |
References
[1] K. J. Disotell and C. L. Rumsey, "Modern CFD validation of turbulent flow separation on axisymmetric afterbodies"
[2] K. J. Disotell and C. L. Rumsey, "Development of an axisymmetric afterbody test case for turbulent flow separation validation", NASA/TM-2017219680, Langley Research Center, Hampton, Virginia, 2017
[3] E. Alaya, C. Grabe, T. Knopp, "Design of a parametrized numerical experiment for a 2D turbulent boundary layer flow with varying adverse pressure gradient and separation behaviour", DLR-Interner Bericht. DLR-IB-AS-GO-2020-109. DLR Institute of Aerodynamics and Flow Technology, 2021
[4] Bassi, F., Botti, L., Colombo, A. C, Ghidoni, A., Massa, F., "On the development of an implicit high-order Discontinuous Galerkin method for DNS and implicit LES of turbulent flows”, European Journal of Mechanics, B/Fluids, 2016
Contributed by: Francesco Bassi, Alessandro Colombo, Francesco Carlo Massa — Università degli studi di Bergamo (UniBG)
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