Comparison of Navier-Stokes and Direct Simulation Monte Carlo Predictions with Separation

Autor: James N. Moss, George R. Inger
Rok vydání: 2007
Předmět:
Zdroj: AIAA Journal. 45:2102-2106
ISSN: 1533-385X
0001-1452
DOI: 10.2514/1.28278
Popis: A N IMPORTANT feature of hypersonicflight vehicleflowfields is shock/boundary layer interaction, and in laminar flow this often provokes a sizable region of separation followed by reattachment. Accordingly, CFD tools are under development for predicting the details of such flows, combined with validating experiments and checks against basic theoretical relations [1]. One aspect of these studies seeks to establish the overlap between the direct simulation Monte Carlo (DSMC) codes designed to treat highly rarefied flows and Navier–Stokes codes appropriate to continuum flows. In particular, one may ask how far into the continuum regime can the DSMC approach be extended if it is finely enough gridded to treat the flow within interaction-induced separation zones. The present paper addresses this question by directly comparing a Navier–Stokes analytical theory of the separation and reattachment streamline angles with the DSMC predictions of Moss and Bird [2], while using Bird’s code called DS2V [3]. Such comparisons provide a severe test of the code because these angles depend sensitively on the local streamwise pressure and skin friction gradients. The paper first derives from a local analysis of the Navier–Stokes equations relationships for the separation and reattachment angles in steady laminar flow on cooled axisymmetric bodies including wall slip effects. Detailed comparisons of their predictions against DSMC code results are then presented for typical separation zones found on the hypersonic double-cone (Fig. 1) and hollow cylinder-flare body geometries. The results support the use of a finely gridded DSMC code to resolve the detailed physics of near continuum flows. II. Theoretical Background
Databáze: OpenAIRE
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