In this paper, we analyze the scaling of velocity structure functions of turbulent thermal convection. Using high-resolution numerical simulations, we show that the structure functions scale similar to those of hydrodynamic turbulence, with the scaling exponents in agreement with She and Leveque's predictions [Phys. Rev. Lett. 72, 336-339 (1994)]. The probability distribution functions of velocity increments are non-Gaussian with wide tails in the dissipative scales and become close to Gaussian in the inertial range. The tails of the probability distribution follow a stretched exponential. We also show that in thermal convection, the energy flux in the inertial range is less than the viscous dissipation rate. This is unlike in hydrodynamic turbulence where the energy flux and the dissipation rate are equal.
Bibliographical noteKAUST Repository Item: Exported on 2021-03-30
Acknowledgements: We are grateful to A. Kumar and A. Chatterjee for sharing their numerical data with us. We acknowledge R. Samuel and M. Sharma for their contributions in the development of the code to calculate structure functions. We thank S. Chakraborty and S. Vashishtha for useful discussions. Our numerical simulations were performed on Shaheen II at Kaust supercomputing laboratory, Saudi Arabia, under the project k1052. This work was supported by the research grants PLANEX/PHY/2015239 from Indian Space Research Organisation, India, and by the Department of Science and Technology, India (INT/RUS/RSF/P-03) for the Indo-Russian project.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Condensed Matter Physics