Turbulence Model Implementation and Verification in the SENSEI CFD Code

Abstract

This paper outlines the implementation and verification of the negative Spalart-Allmaras turbulence model into the SENSEI CFD code. The SA-neg turbulence model is implemented in a flexible, object-oriented framework where additional turbulence models can be easily added. In addition to outlining the new turbulence modeling framework in SENSEI, an overview of the other general improvements to SENSEI is provided. The results for four 2D test cases are compared to results from CFL3D and FUN3D to verify that the turbulence models are implemented properly. Several differences in the results from SENSEI, CFL3D, and FUN3D are identified and are attributed to differences in the implementation and discretization order of the boundary conditions as well as the order of discretization of the turbulence model. When a solid surface is located near or intersects an inflow or outflow boundary, higher order boundary conditions should be used to limit their effect on the forces on the surface. When the turbulence equations are discretized using second order spatial accuracy, the edge of the eddy viscosity profile seems to be sharper than when a first order discretization is used. However, the discretization order of the turbulence equation does not have a significant impact on output quantities of interest, such as pressure and viscous drag, for the cases studied.

Computations of the BeVERLI Hill Three-dimensional Separating Flow Model Validation Cases

“…VT utilized two distinct CFD solvers for their simulations. First, the VT in-house solver SENSEI [23,24] and second, the commercially available ANSYS Fluent solver [25]. In SENSEI, the inviscid flux discretization was performed using Roe's flux difference splitting [26] with MUSCL extrapolation to achieve a second-order accurate scheme.…”

An Improved Framework of GPU Computing for CFD Applications on Structured Grids using OpenACC

“…For more details on the theory and background see Derlaga et at. [25], Jackson et al [26] and Xue et al [27].…”

“…2. Description of the CFD code: SENSEI SENSEI (Structured, Euler/Navier-Stokes Explicit-Implicit Solver) is our in-house 2D/3D flow solver initially developed by Derlaga et al [25], and later extended to a turbulence modeling code base through an object-oriented programming manner by Jackson et al [26] and Xue et al [27]. SENSEI is written in modern Fortran and is a multi-block finite volume CFD code.…”

Iterated discretization error transport equations for laminar and turbulent flows

“…SENSEI (Structured, Euler/Navier–Stokes Explicit‐Implicit) is a compressible, cell‐centered, finite‐volume flow solver.The code is initially designed to solve the Euler and laminar Navier Stokes equations 1 . The implementation details of Spalart–Allmaras (SA) model in the code and verification results using test cases given on the Turbulence Modeling Resource (TMR) website 2 can be found in Reference 3. Results from CFL3D 4 and FUN3D 5 are used to confirm whether the SA model is implemented correctly in SENSEI.…”