LAUSR

The stability of the contact interface for radial shock tubes is investigated as a model for explosive dispersal. The advection upstream splitting method with velocity and pressure diffusion (AUSM+-up) is used to solve for the radial base flow. To investigate the stability of the resulting contact interface, perturbed governing equations are derived assuming harmonic modes in the transverse directions. The perturbed harmonic flow is solved by assuming an initial disturbance and using a perturbed version of AUSM+-up derived in this paper. The intensity of the perturbation near the contact interface is computed and compared to theoretical results obtained by others. Despite the simplifying assumptions of the theoretical analysis, very good agreement is observed. Not only can the magnitude of the instability be predicted during the initial expansion, but also remarkably the agreement between the numerical and theoretical results can be maintained through the collision between the secondary shock and the contact interface. Since the theoretical results only depend upon the time evolution of the base flow, the stability of various modes could be quickly investigated without explicitly solving a system of partial differential equations for the perturbed flow.The stability of the contact interface for radial shock tubes is investigated as a model for explosive dispersal. The advection upstream splitting method with velocity and pressure diffusion (AUSM+-up) is used to solve for the radial base flow. To investigate the stability of the resulting contact interface, perturbed governing equations are derived assuming harmonic modes in the transverse directions. The perturbed harmonic flow is solved by assuming an initial disturbance and using a perturbed version of AUSM+-up derived in this paper. The intensity of the perturbation near the contact interface is computed and compared to theoretical results obtained by others. Despite the simplifying assumptions of the theoretical analysis, very good agreement is observed. Not only can the magnitude of the instability be predicted during the initial expansion, but also remarkably the agreement between the numerical and theoretical results can be maintained through the collision between the secondary shock and the cont...