Showing papers by "Manhar R. Dhanak published in 2002"
TL;DR: The results of large-eddy simulations (LES) of turbulent thermal convection generated by surface cooling in a finite-depth stably stratified horizontal layer with an isothermal bottom surface are presented in this article.
Abstract: We present the results of large-eddy simulations (LES) of turbulent thermal convection generated by surface cooling in a finite-depth stably stratified horizontal layer with an isothermal bottom surface The flow is a simplified model of turbulent convection occurring in the warm shallow ocean during adverse weather events Simulations are performed in a 6 × 6 × 1 aspect ratio computational domain using the pseudo-spectral Fourier method in the horizontal plane and finite-difference discretization on a high-resolution clustered grid in the vertical direction A moderate value of the Reynolds number and two different values of the Richardson number corresponding to a weak initial stratification are considered A version of the dynamic model is applied as a subgrid-scale (SGS) closure Its performance is evaluated based on comparison with the results of direct numerical simulations (DNS) and simulations using the Smagorinsky model Comprehensive study of the spatial structure and statistical properties of the developed turbulent state shows some similarity to Rayleigh–Benard convection and other types of turbulent thermal convection in horizontal layers, but also reveals distinctive features such as the dominance of a large-scale pattern of descending plumes and strong turbulent fluctuations near the surface
26 citations
30 Sep 2002
TL;DR: In this article, the authors contribute to the development of physics-based numerical models for accurate assessment and prediction of the ocean environment, and develop state of the art system for oceanographic observations from one or more AUV surveyor platforms.
Abstract: : The principal long-term goals of this work are to (i) contribute to the development of physics-based numerical models for accurate assessment and prediction of the ocean environment, and (ii) develop state of the art system for oceanographic observations from one or more AUV surveyor platforms. Our contribution is based on developing accurate parameterization of the active small-scale processes in the water column through observations from fixed and mobile AUV platforms. The parameterizations are needed to correctly model subgrid scale processes in predictive numerical models. The aim is to develop the necessary data bank to help parameterize the sub-grid processes under various, measured background conditions.