Abstract
Numerical simulations of the fully compressible Navier-Stokes equations are used to study the transition from simple-periodic {open_quotes}harmonic{close_quotes} thermal convection to chaotic thermal convection as the Rayleigh number Ra is increased. The simulations suggest that a sharp discontinuity in the relationship between the Nusselt number Nu (the ratio of the total heat flux to the Fourier heat flux) and the Rayleigh number is associated with this transition in flow morphology. This drop in the Nusselt number is also seen in the data reported in independent experiments involving the convection of two characteristically different fluids{emdash}liquid mercury [Phys. Rev. E {bold 56}, R1302 (1997)] (a nearly incompressible fluid with Prandtl number Pr=0.024) and gaseous helium [Phys. Rev. A {bold 36}, 5870 (1987)] (a compressible fluid with unit Pr). The harmonic flow generates a dual-maximum (quasiharmonic) temperature histogram, while the chaotic flow generates a single-maximum histogram at the center point in the simulated cell. This is consistent with the temperature distributions reported for the convecting mercury before and after the drop in Nu. Our simulations also suggest a hysteresis in the Nu-Ra curve linking the two distinctly different flow morphologies, heat fluxes, and temperature-fluctuation histograms at the same Rayleigh number. {copyright} {ital 1998} {italmore » The American Physical Society}« less
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.