Heat and Mass Transfer
S. Mohammed Ibrahim; K. Suneetha
Abstract
The present paper was aimed to study the effects of variable thermal conductivity and heat generation on the flow of a viscous incompressible electrically conducting fluid in the presence of a uniform transverse magnetic field, thermal radiation, porous medium, mass transfer, and variable free stream ...
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The present paper was aimed to study the effects of variable thermal conductivity and heat generation on the flow of a viscous incompressible electrically conducting fluid in the presence of a uniform transverse magnetic field, thermal radiation, porous medium, mass transfer, and variable free stream near a stagnation point on a non-conducting stretching sheet. Equations of continuity, momentum, energy, and mass were transformed into ordinary differential equations and solved numerically using shooting method. Velocity, temperature, and concentration distributions were numerically discussed and presented in the graphs. Skin-friction coefficient, the Nusselt number, and Sherwood number on the sheet were derived and discussed numerically. Their numerical values for various values of physical parameters were presented in the tables. It was found that temperature increased with increasing radiation parameter, R, and concentration decreased with increasing the Schmidt number, Sc. The numerical predications were compared with the existing information in the literature and a good agreement was obtained.
Control
R. Mestiri*; F. Aloui; S. Ben Nasrallah
Abstract
The technique used to control the airflow is based on the electro-hydrodynamic actuator which is also called plasma actuator. This actuator ensures the airflow control thanks to the electric wind created by the electrical corona discharge. This ionic wind is developed at the profile surface tangential ...
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The technique used to control the airflow is based on the electro-hydrodynamic actuator which is also called plasma actuator. This actuator ensures the airflow control thanks to the electric wind created by the electrical corona discharge. This ionic wind is developed at the profile surface tangential to the initial free airflow so that it has a significant effect on the boundary layer flow. The studied profile was a NACA4412 airfoil. The electro-hydrodynamic actuator was placed at the surface of the NACA profile. The PIV visualizations made at angle of attack of 18° show an earlier flow reattachment to the profile surface when the plasma actuator is active. PIV measurements confirm that downstream of the actuator, when the discharge is ON, the wall velocity gradient is increased as illustrated by the velocity profiles taken at several positions on the NACA4412 wall. Then the plasma actuator can decrease the boundary layer thickness.