Unstructured Finite Element Method Research Articles

Turbulence models for unstructured finite element calculations

AbstractAn unstructured finite element method is presented for calculation of turbulent flow fields about aerospace configurations. Algebraic, one‐equation, and two‐equation turbulence models are implemented and compared. A new procedure for implementing an unstructured algebraic model without an auxiliary structured grid is presented. The overall procedure is applied to simulation of flow about launch vehicle configurations. The turbulence models are evaluated for calculation of flow fields about a forebody with shock induced separation. For this case. the one‐equation model gives better predictions. An inviscid flow field about a complete launch vehicle with multiple boosters is also evaluated to demonstrate the overall procedure.

Unstructured adaptive remeshing finite element method for dusty shock flow

The passage of planar shocks in a dusty gas was investigated to note effects due to particle loading and initial shock Mach number. Two-phase flow equations have been added to a conservative, monotonic flow solver to allow study of compressible particle and droplet flows, which are of importance for shock propagation in two-phase flows and spray propulsion systems. The formulation developed herein employed a conservative Eulerian treatment for the gas and particle phases. The computations were performed using the finite element method-flux corrected transport (FEM-FCT) scheme, which has shown excellent predictive capability of various compressible flows which include both strong and weak shocks. The flux limiting technique was modified to provide monotonic particle velocity fields to increase the scheme's computational stability. Adaptive unstructured methodology based on adapting to high gradients of both the fluid and particle densities was used in conjunction with the conservative shock-capturing scheme to adequately resolve strong flowfield gradients. The shock attenuation of this scheme was then compared with previous experimental and numerical results and was found to yield robust predictions. Various interphase coupling terms were also considered to note their effect on the shock attenuation.