Modeling the effects of small turbulent scales on the drag force for particles below and above the Kolmogorov scale

AbstractAhmed Body is a standard and simplified shape of a road vehicle that's rear part has an important role in flow structure and it's drag force. In this paper flow control around the Ahmed body with the rear slant angle of 25° studied by using the plasma actuator system situated in middle of the rear slant surface. Experiments conducted in a wind tunnel in two free stream velocities of U = 10m/s and U = 20m/s using steady and unsteady excitations. Pressure distribution and total drag force were measured and smoke flow visualization carried out in this study. The results showed that at U = 10m/s using plasma actuator suppress the separated flow over the rear slant slightly and be effective on pressure distribution. Also, total drag force reduces in steady and unsteady excitations for 3.65% and 2.44%, respectively. At U = 20m/s, using plasma actuator had no serious effect on the pressure distribution and total drag force.

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EVALUATION OF REAR SPOILER PITCH ANGLES VARIATION IN DRAG FORCE ON A SQUAREBACK AHMED BODY

10.26678/abcm.cobem2019.cob2019-0828 ◽

2019 ◽

Author(s):

Vagner Ferreira de Oliveira

Keyword(s):

Drag Force ◽

Rear Spoiler ◽

Ahmed Body

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OUTDOOR TESTS OF A TOWED BOAT MODEL WITH FUEL COMBUSTION IN A BOTTOM CAVITY

NONEQUILIBRIUM PROCESSES: RECENT ACCOMPLISHMENTS ◽

10.30826/nepcap9a-45 ◽

2020 ◽

Author(s):

S. M. FROLOV ◽

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S. V. Platonov ◽

K. A. AVDEEV ◽

V. S. AKSENOV ◽

...

Keyword(s):

Drag Force ◽

Direct Contact ◽

Propulsion System ◽

Hydrodynamic Drag ◽

Atmospheric Air ◽

System A ◽

Bottom Cavity ◽

Gas Cavity ◽

System Power ◽

Gas Supply

To reduce the hydrodynamic drag force to the movement of the boat, an artificial gas cavity is organized under its bottom. Such a cavity partially insulates the bottom from direct contact with water and provides “gas lubrication” by means of forced supply of atmospheric air or exhaust gases from the main propulsion system. A proper longitudinal and transverse shaping of the gas cavity can significantly (by 20%-30%) reduce the hydrodynamic drag of the boat at low (less than 3%) consumption of the propulsion system power for gas supply.

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