Detached Eddy Simulation of Supersonic Shear Layer Wake Flows

One challenge of numerical investigations of unsteady super- and hypersonic flow fields is the study of the turbulent wake at complex vehicle configurations. A recent promising approach is the technique of detached-eddy simulation (DES) proposed by Spalart et.al. Detached-eddy simulation is a hybrid approach for the modelling of turbulent flow fields at complex geometries. The intention of the current work is an investigation of the shear flow in the wake of a blunt cylinder at M=2.4 at high Reynolds numbers. This is used as a basic configuration for re-entry vehicles with a blunt base. Additionally simulations of the SARA capsule, a facility conceived to be a recovery orbital platform to perform orbital flights, are carried out to give a practical demonstratin of DES modelling for hypersonic flight To ensure turbulent wake flow the trajectory point at M=5.1, Re= 20 10^6 was chosen. The influence of unsteady loads, generated by the turbulent wake flow was investigated for this vehicle

Implementation and Performance Evaluation of k − kL Turbulence Model

The k − kL turbulence model is implemented into the DLR TAU code and the correctness of the model implementation is examined by computing the verification test cases from the NASA Turbulence Modeling Resource website and comparing the results with the predictions delivered by other codes. Later, the model performance is assessed for a range of test cases. Finally, its applicability to wing-body junction flows is evaluated

Numerical Simulation of Vortex-Dominated Flows Using Advanced Physical Models

The capabilities of Reynolds stress model compared to eddy-viscosity RANS turbulence models and scale-resolving simulation methods for the flows characterized by separation from smooth surfaces and subsequent vortex formation are assessed. To this end, the flow over a delta wing and a diamond wing at the incidence angle of 13 deg. and 12 deg., respectively, are investigated. Predictions obtained for the aforementioned configurations by different approaches are compared to each other and to experiments. In this paper, improvements and detriments observed in Reynolds stress model predictions compared to RANS predictions and to scale-resolving simulations are presented

Einfluss des Turbulenzmodells auf die Vorhersage der Eckenströmung am NASA Common Research Model

Es werden numerische Simulationen der Strömung um das NASA Common Research Model (CRM) mit verschiedenen Turbulenzmodellen vorgestellt. Ein besonderes Augenmerk liegt dabei auf der Vorhersage einer Eckenablösung am Flügel-Rumpf-Übergang, die im Experiment im Auslegungspunkt nicht auftritt. Mit linearen Wirbelviskositätsmodellen wird eine Eckenablösung vorausgesagt, die mithilfe der sog. QCR-Erweiterung, einer nichtlinearen Modellerweiterung, reduziert wird. Mit einem differentiellen Reynolds-Spannungsmodell tritt sie dagegen auf den verwendeten Netzen überhaupt nicht auf

Assessment of g-Equation Formulation for a Second-Moment Reynolds Stress Turbulence Model

In this work, an alternative formulation for the specific dissipation rate in the Speziale-Sarkar-Gatski / Launder-Reece-Rodi Reynolds stress model is assessed. Here, g=1/omega) is considered as an alternative for ! and the performance of the g-equation is assessed for a range of test cases, which include validation test cases to flows around industry relevant configurations. Comparison of predictions shows that the predictions are similar to omega predictions and yet demonstrate less dependency on the near-wall grid resolution due to the natural boundary condition at solid walls

Simulation of Transonic Flows with Differential Reynolds Stress Models

In this work, the Stress-omega and SSG/LRR-omega differential Reynolds stress models are applied to aeronautical industry relevant transonic flow test cases in order to assess the model performance concerning the shock location. For the test cases investigated here, the SSG/LRR-omega reproduced experimental shock positions whereas the Stress-omega model consistently predicted the shock location too far downstream

Second-Moment RANS Model Verification and Validation using the Turbulence Model Resource Website

The implementation of the SSG/LRR-omega differential Reynolds stress model into the NASA flow solvers CFL3D and FUN3D and the DLR flow solver TAU is verified by studying the grid convergence of the solution of three different test cases from the Turbulence Modeling Resource Website. The model's predictive capabilities are assessed based on four basic and four extended validation cases also provided on this website, involving attached and separated boundary layer flows, effects of streamline curvature and secondary flow. Simulation results are compared against experimental data and predictions by the eddy-viscosity models of Spalart-Allmaras (SA) and Menter's Shear Stress Transport (SST)