We describe a fluid flow problem in astrophysics which also has applications in other areas of science and engineering. A study of the convection process of heat and material transfer in the outer layers of stars like the sun has led to an extensive investigation of compressible convection in a layer confined between two plates. This work attempts to reach the highest possible Reynolds number regime. High effective Reynolds numbers are achieved by using the Picccwise-Parabolic Method (PPM) to solve the Euler equations. Attempts to demonstrate the validity of this approach have led to related studies of compressible vortex dynamics and of compressible homogeneous turbulence. Results of simulations of compressible convection in both 2-D and in 3-D will be presented. These flows arc so complicated that they can best be appreciated when high-resolution color images of important flow variables are animated, so that the dynamics can be seen directly. A few snapshots arc presented here, and video movies are available from the authors. Visualization techniques which have been developed in this work, particularly those designed for the 3-D flows, are briefly discussed. The Piece wise-Parabolic Method (PPM) is briefly described. In the context of compressible vortex dynamics, results of the PPM code are compared directly to accurate Navier-Stokes simulations. This comparison indicates that if a viscosity is to be used in such simulations which can be rigorously justified on physical grounds, and if the behavior at a very high Reynolds number is sought, then vastly greater computer resources must be devoted to the problem than are required by the PPM code.
|Original language||English (US)|
|State||Published - 1990|
|Event||28th Aerospace Sciences Meeting, 1990 - Reno, United States|
Duration: Jan 8 1990 → Jan 11 1990
|Other||28th Aerospace Sciences Meeting, 1990|
|Period||1/8/90 → 1/11/90|
Bibliographical noteFunding Information:
The work reported herc was pcrformed at the University of Minnesota Supercomputcr Institute. The University of Minnesota has given a great dcal of support to this work. In addition to research startup grants, the university has made substantial grants of time on its Cray-2 computer and has supponed purchases of graphics oriented equipment from Silicon Graphics and Gould. Equipmcnt donations from Sun Microsystcms and Gould wcre also essential in supponing this work. Visualization hardware was also purchascd undcr an equipmcnt grant from the Air Force Officc of Scientific Research, grant AFOSR-86-0239. More rcccnlly, work rcportcd hcrc has bccn supported by the Officc of Energy Rcscarch of the Department of Energy, undcr contract no. DE-FG02-87ER25035, and by the National Science Foundation, undcr grant AST-8611404. Thc prcscnt upgrade of our visualization equipment is supported by thcsc two agencies and by a donation of equipment from Imprimis Technology.
© 1990 American Enslilute of Aeronaulics tmd Astronautics, Inc. All rights reserved.