Large Eddy Simulations of thermal boundary layer developments in a turbulent channel flow under asymmetrical heating

2017 ◽  
Vol 151 ◽  
pp. 159-176 ◽  
Author(s):  
Morgane Bellec ◽  
Adrien Toutant ◽  
Gabriel Olalde
Keyword(s):  
Boundary Layer ◽  
Channel Flow ◽  
Thermal Boundary Layer ◽  
Turbulent Channel Flow ◽  
Large Eddy Simulations ◽  
Large Eddy

Large Eddy Simulations of Thermal Boundary Layer Spatial Development in a Turbulent Channel Flow

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Marc Sanchez ◽  
Frédéric Aulery ◽  
Adrien Toutant ◽  
Françoise Bataille
Keyword(s):  
Boundary Layer ◽  
Channel Flow ◽  
Thermal Boundary Layer ◽  
Turbulent Channel Flow ◽  
Spatial Development ◽  
Large Eddy Simulations ◽  
Boundary Layer Development ◽  
Large Eddy ◽  
The Mean ◽  
Heat Transfers

This article presents Large Eddy Simulations of thermal boundary layer spatial development in a low-Mach number turbulent channel flow. A coupling between isothermal biperiodic channel and anisothermal open channel is done to obtain a fully developed turbulent inlet. The interaction between a high temperature gradient and a turbulent flow is studied during the thermal boundary layer development. Turbulence and temperature quantities are analyzed for both streamwise and wall-normal directions. The results show how the asymmetrical heating modifies the velocity of the flow. The correlation between turbulence and heat transfers is studied. The mean and the fluctuation profiles are found to be asymmetrical. They evolve along the channel and are perturbed by the thermal gradient. Fluctuation destruction and creation areas in the length of the channel are highlighted.

scholarly journals Temporal acceleration of a turbulent channel flow

2017 ◽  
Vol 835 ◽  
pp. 471-490 ◽  
Author(s):  
A. Mathur ◽  
S. Gorji ◽  
S. He ◽  
M. Seddighi ◽  
A. E. Vardy ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Laboratory Experiments ◽  
Transient Flow ◽  
Turbulent Channel Flow ◽  
Transition Process ◽  
Direct Numerical Simulations ◽  
Large Eddy Simulations ◽  
Large Eddy ◽  
Initial Turbulence ◽  
Striking Contrast

We report new laboratory experiments of a flow accelerating from an initially turbulent state following the opening of a valve, together with large eddy simulations of the experiments and extended Stokes first problem solutions for the early stages of the flow. The results show that the transient flow closely resembles an accelerating laminar flow superimposed on the original steady turbulent flow. The primary consequence of the acceleration is the temporal growth of a boundary layer from the wall, gradually leading to a strong instability causing transition. This extends the findings of previous direct numerical simulations of transient flow following a near-step increase in flow rate. In this interpretation, the initial turbulence is not the primary characteristic of the resulting transient flow, but can be regarded as noise, the evolution of which is strongly influenced by the development of the boundary layer. We observe the spontaneous appearance of turbulent spots and discontinuities in the velocity signals in time and space, revealing rich detail of the transition process, including a striking contrast between streamwise and wall-normal fluctuating velocities.

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