Mohsen Jahanmiri
, Shiraz University of Technology, Iran
[ 1 ] - EXPERIMENTAL INVESTIGATION OF DRAG REDUCTION ON AHMED MODEL USING A COMBINATION OF ACTIVE FLOW CONTROL METHODS
Aerodynamic drag is an important factor in vehicles fuel consumption. Pressure drag which is the main component of total drag is a result of boundary layer separation from vehicle surface. Flow control methods are applied to avoid or at least delay separation. Depending upon whether these methods consume energy to control the flow or not, they are called active or passive control methods. In th...
[ 2 ] - The Perturbation Flow Field Associated With Passage of Turbulent Spot (RESEARCH NOTE)
The flow field associated with the passage of the turbulent spot in a 3–D duct with streamline divergence under zero pressure gradients was investigated and displayed as contour plots of the velocity perturbation in plan and elevation view of the spot. It suggests that, streamline divergence has no strong effect on the internal structure of the spot and eddies and their propagation in the downs...
[ 3 ] - On Interaction of T S Waves and 3 D Localized Disturbance in a Divergent Flow Under Zero Pressure Gradient
To simulate the effect of free st ream turbulence on turbulent spot formation, experiments were conducted on the interaction of localized three-dimensional disturbances with the harmonic waves in a laminar boundary layer on a flat plate. Experiments conducted in three-dimensional diverging flow (but zero pressure gradient) show, while individually the disturbances decay downstream, their intera...
[ 4 ] - Static Pressure Distribution in an Excited Jet: Some Observations (RESEARCH NOTE)
A plane subsonic jet was subjected to periodic oscillations in the near nozzle region by a twin vane system. During excitation, the jet was found to spread significantly and entrain mass much more than its steady counterpart. Time averaged static pressure measured in the flow field with a disc probe exhibited prominent well defined suction regions different from that of a steady jet.
[ 5 ] - A Mthod for Generating the Turbulent Intermittency Function
A detection method based on sensitization of a squared double differentiated signal is developed which discriminates the turbulent zones from laminar zones quite accurately. The procedure adopts a variable threshold and a variable hold time of the order of the Kolmogorov time scale. The output file so generated, includes all the information for further analysis of the turbulent signal.
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