Time Accurate Computation of Unsteady Shock Tunnel Flow with Coupled Diaphragm Ruptude Mechanics
Abstract
This report reviews work performed toward the goal of simulating time accurately the initiation of flow in a hypersonic shock tunnel, including coupled diaphragm rupture mechanics. A solution-adaptive mesh Naver-Stokes code was modified to improve mesh distribution for rapidly moving flow features, to include boundary surface motion, and to incorporate weight function and stability enhancements. A simulation of an unadapted grid blade-type shock tube diaphragm opening actuated by algorithm was completed. A repeat of these simulations with mesh adaptation revealed problems with the adaptive algorithm related to the interaction with the grid block structure that were only partially alleviated by limiting mesh movement at the blade tip. Plane strain and axisymmetric finite-element programs have been developed for the investigation of dynamic inelastic deformation and rupture of a shock-tube diaphragm. Results indicate that crack nucleation occurs when compressive waves at high pressures reflect off the rear of the diaphragm as tensile waves that are a precursor to crack initiation. Results from this study, indicate that stress fields, stress gradients, and plastic strains at the free-edge or at the crack or notch are physically large enough, at the higher pressures, to result in crack nucleation, diaphragm rupture, and material separation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 29, 1999
- Accession Number
- ADA378084
Entities
People
- D. S. Mcrae
- M.A. Zikry
Organizations
- North Carolina State University