+ Visit NASA.gov + Contact NASA   + Home Collection > NASA  Author > Duh, J. C.  NASA Center > Glenn Research Center  Publication Year > 1981-1990 > 1989  Subject > D-F > Fluid Mechanics And Heat Transfer  Availability Options > Order From Other Sources  Item/Media Type > Preprint  Item/Media Type > NASA Report > Technical Memorandum (TM)  Note: Start a new navigation search by selecting a link above     Previous Record | Next Record + Back to Results   + Printer Friendly Title: Numerical modeling of enclosure convection Author(s): Duh, J. C. Abstract: A numerical study on the steady and unsteady natural convection in two-dimensional rectangular enclosures has been performed by a time-accurate ADI finite difference scheme. The study covered a range of Rayleigh numbers between 1000 and 10 to the 7th, aspect ratios between 0.2 and 10.0, and tilt angles between -90 (heating from bottom) and 90 deg (heating from top). Various Prandtl numbers have been studied, but only the results of water (Pr = 7.0) are reported here due to space limitations. The physics revealed, however, includes the convection phenomena and the Rayleigh-Benard stability, as well as the combined mechanism of these two. The onset of secondary cells is determined by using a velocity map, which is simpler and cleaner, instead of a streamline plot. The critical Ra number for the occurrence of these secondary cells is shown to be lower than can be detected by experimental studies. On the Rayleigh-Benard stability part, a second transition from stable single-cell convection to periodic multicellular convection is disclosed. NASA Center: Glenn Research Center Publication Date: Oct 1, 1989 Document Source: Other Sources No Digital Version Available: Go to Tips On Ordering Document ID: 19900026456 Accession ID: 90A13511 Publication Information: Number of Pages = 9 Report Number: IAF PAPER 89-403 Keywords: ALTERNATING DIRECTION IMPLICIT METHODS; COMPUTATIONAL FLUID DYNAMICS; CONVECTIVE FLOW; FREE CONVECTION; NUMERICAL FLOW VISUALIZATION; TWO DIMENSIONAL FLOW; COMPUTATIONAL GRIDS; FINITE DIFFERENCE THEORY; PRANDTL NUMBER; RELAXATION METHOD (MATHEMATICS); SPACE COMMERCIALIZATION; Notes: IAF, International Astronautical Congress, 40th, Malaga, Spain, Oct. 7-13, 1989. 9 p. Accessibility: Unclassified; Copyright; Unlimited; Publicly available; Updated/Added to NTRS: 2004-11-03 + Back to Top + Sponsored by the NASA Scientific and Technical    Information Program + 2004 Vision for Space Exploration + Freedom of Information Act + NASA Web Privacy Policy and Important Notices + NASA Disclaimers, Copyright Notice,    and Terms and Conditions of Use NASA Official: Calvin Mackey Page Curator: NASA Center for AeroSpace Information (help@sti.nasa.gov) Last Updated: July 5, 2007