skip to main content

DOE PAGESDOE PAGES

Title: Scaling of heat transport near onset in rapidly rotating convection

Here, we consider the scaling of heat transport in the geostrophic regime of rotating Rayleigh–Bénard convection near onset for small Ekman number Ek from the perspective of weakly nonlinear theory. We show that available heat transport data from numerical simulation [1] for Ek < 10 -5 for Pr = 1 are consistent with weakly nonlinear theory for ϵ = Ra / Ra c - 1 < 1. In particular, we show that the numerical data are consistent with Nu - 1 = aϵ + bϵ 2 with a ≈ 2 and b ≈ 3 with weak dependence of the coefficients on Ek. The coefficient a is consistent with calculations of weakly nonlinear theory and with experimental data at much higher Ek. The positive sign of b is also suggested by those experimental data. The magnitude and trend of the numerical data for larger Ra are consistent with experimental data with similar Pr ~ 1. The steep scaling of Nu ~ (Ra / Ra c) 3 noted elsewhere for Ra / Ra c < 2 is shown to be an artifact of being close to onset where the effective power-law slope depends sensitively on the magnitude of the coefficients a andmore » b. Similar arguments apply to Pr = 7 numerical data although the weakly nonlinear expansion appears valid for a smaller range of ϵ than in the Pr = 1 case.« less
Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Nonlinear Studies (CNLS)
Publication Date:
Report Number(s):
LA-UR-15-24568
Journal ID: ISSN 0375-9601
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physics Letters. A
Additional Journal Information:
Journal Volume: 379; Journal Issue: 37; Journal ID: ISSN 0375-9601
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Planetary Sciences; rotation; convection; heat transport
OSTI Identifier:
1457247
Alternate Identifier(s):
OSTI ID: 1359747