Recent Enhancements to USM3D Unstructured Flow Solver for Unsteady Flows

Abstract

The NASA USM3D unstructured flow solver is undergoing extensions to address dynamic flow problems in support of NASA and NAVAIR efforts to study the applicability of Computational Fluid Dynamics tools for the prediction of aircraft stability and control characteristics. The initial extensions reported herein include two second-order time stepping schemes, Detached-Eddy Simulation, and grid motion. This paper reports the initial code verification and validation assessment of the dynamic flow capabilities of USM3D. The cases considered are the classic inviscid shock-tube problem, low Reynolds number wake shedding from a NACA 0012 airfoil, high Reynolds number DES-based wake shedding from a 4-to-1 length-to-diameter cylinder, and forced pitch oscillation of a NACA 0012 airfoil with inviscid and turbulent flow.

Computational Methods for Stability and Control (COMSAC): The Time Has Come

“…Work is well underway for each of the above capabilities. 22,23 The examples to be illustrated for this status report are from analyses of the S&C characteristics of the F/A-18E/F. This aircraft, in its pre-production version, experienced abrupt wing stall which resulted in its susceptibility to asymmetric wing stall, or wing drop.…”

Enhancement of USM3D Unstructured Flow Solver for High-speed High-Temperature Shear Flows

“…It also contains some additional special BCs for jet exhaust and intake, a propeller/rotor actuator disk model, and passive porosity [19]. The most recent enhancements to USM3D are second-order time accuracy, Detached Eddy Simulation (DES) capability, dynamic grid motion [20], and overset-grid moving body capability [21].…”

CFD Computations for a Generic High-Lift Configuration Using TetrUSS

“…Spatial discretization is accomplished by a novel reconstruction process, based on an analytical formulation for computing solution gradients within tetrahedral cells. The solution is advanced in time by a second-order Newton time step scheme 16 , or to a steady-state condition by an implicit backward-Euler scheme. USM3D supports an array of useful boundary conditions (BCs).…”