ライブラリ登録: Guest
ICHMT DL ホーム 今年 アーカイブ 執行委員会 熱・物質移動国際センター

Analysis of Turbulent Structures of Natural Convection in a Vertical Channel by using DNS

DOI: 10.1615/ICHMT.2006.TurbulHeatMassTransf.1010
pages 491-494

Koichi Tsujimoto
Department of Mechanical Engineering, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho,Tsu-city, Mie-Pref. Japan

N. Ohya
Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho,Tsu-city, Mie-Pref. Japan

Toshihiko Shakouchi
Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho,Tsu-city, Mie-Pref. Japan

Toshitake Ando
Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho,Tsu-city, Mie-Pref. Japan

要約

The objective is to clarify the mechanisms of heat transfer under the buoyancy effect. A direct numerical simulation (DNS) of natural convection in a differentially heated vertical slot is performed with the Boussinesq approximation. The discretization of computation is carried out with a spectral method for three directions. The Rayleigh number (Ra), which is defined based on an slot width and the temperature difference between both walls, is 5.4 × 105. This study also conducts a more detailed investigation on turbulence structures. The results reveals that quasi-streamwise vortices are not formed in the near-wall region and a large-scale streamwise vortical structure is dominant in the core region of the slot. We extract this large-scale structure by the proper orthogonal decomposition (POD). The energetic mode is characterized by rotational motion in which the axis is in the streamwise direction and the scale is approximately equal to the width of flow passage. Furthermore, the reconstructed flow structures with low-dimensional modes of velocity are highly correlated with those of thermal field. Therefore, these findings recommend that the streamwise-directed vortex must be controlled in order to effectively enhance the heat exchange.

ICHMT Digital Library

Bow shocks on a jet-like solid body shape. Thermal Sciences 2004, 2004. Pulsed, supersonic fuel jets - their characteristics and potential for improved diesel engine injection. PULSED, SUPERSONIC FUEL JETS - THEIR CHARACTERISTICS AND POTENTIAL FOR IMPROVED DIESEL ENGINE INJECTION
View of engine compartment components (left). Plots of temperature distributions in centreplane, forward of engine (right). CHT-04 - Advances in Computational Heat Transfer III, 2004. Devel... DEVELOPMENT AND CURRENT STATUS OF INDUSTRIAL THERMOFLUIDS CFD ANALYSIS
Pratt & Whitney's F-135 Joint Strike Fighter Engine under test in Florida is a 3600F class jet engine. TURBINE-09, 2009. Turbine airfoil leading edge stagnation aerodynamics and heat transfe... TURBINE AIRFOIL LEADING EDGE STAGNATION AERODYNAMICS AND HEAT TRANSFER - A REVIEW
Refractive index reconstructed field. (a) Second iteration. (b) Fourth iteration. Radiative Transfer - VI, 2010. Theoretical development for refractive index reconstruction from a radiative ... THEORETICAL DEVELOPMENT FOR REFRACTIVE INDEX RECONSTRUCTION FROM A RADIATIVE TRANSFER EQUATION-BASED ALGORITHM
Two inclusion test, four collimated sources. Radiative Transfer - VI, 2010. New developments in frequency domain optical tomography. Part II. Application with a L-BFGS associated to an inexa... NEW DEVELOPMENTS IN FREQUENCY DOMAIN OPTICAL TOMOGRAPHY. PART II. APPLICATION WITH A L-BFGS ASSOCIATED TO AN INEXACT LINE SEARCH