A Case Study of Verifying and Validating an Astrophysical Simulation Code

摘要

We present a case study of verifying and validating FLASH, a parallel adaptive-mesh hydrodynamics code for studying the compressible, reactive flows found in many astrophysical environments. We briefly describe the astrophysics Problems of interest and physics relevant to these problems. We discuss our methodology for verification and Validation, and we describe our automated testing process for Software verification. We present the result of one verification test that typifies our methodology for algorithmic verification. We present the results of two fluid dynamics Validation tests in which we compared simulations to laboratory results. The first is of a laser-driven shock propagating through a multi-layer target, a configuration subject to both Rayleigh-Taylor and Richtmyer-Meshkov instabilities. The second test is a classic Rayleigh-Taylor instability, where a heavy fluid is supported against the force of gravity by a light fluid. Our simulations of the multi-layer target experiments showed good agreement with the experimental results, but our simulations of the Rayleigh-Taylor instability did not agree well with the experimental results. We discuss our findings and potential reasons for the discrepancies.