IMPROVEMENT OF DYNAMICS PROPCRTICS OF NACA 23015  WING MODEL USING INTERNAL VOICE ACTION TECHNIQUES

	IMPROVEMENT OF DYNAMICS PROPCRTICS OF NACA 23015 WING MODEL USING INTERNAL VOICE ACTION TECHNIQUES
AL-TAQANI
Article 1, Volume 22, Issue 3, 2009, Pages 0-0
Abstract
This work studies the operation of controlling the separation of flow (delaying the separation) on a cambered unsymmetrical surface which leads to improving the lift coefficient by using internal excitation technique, for a range of frequency at a constant density level (80 dB) with changing its position. The experimental study was made on two locally –manufactured unsymmetrical wood models of airfoil type (NACA 23015). The position of the excitation first one is (11.5% chord) from the leading edge, while the second one’s is (6% chord) from the leading edge. The dimension of the airfoil is (150 mm) chord length and (305mm) length. The experiments were made at a frequency range (50 ,100,150,200,250,300,350,400) Hz, and the angles of attack were (3ο,6ο,9ο,12ο), in an open subsonic wind tunnel for (Re.=3.3 x105) with using internal sound excitation production devices, excitation circuit (frequency generator, power amplifier, excitation sources). The tests showed the effect of internal acoustic excitation frequency value and changing its position on the aerodynamic coefficients. The aerodynamic coefficient was improved at frequency value (150Hz) for all the angles of attack, this is because this frequency is close from the frequency of cavity resonance at which the shear layer stress frequency equals the acoustic excitation frequency which leads to converting the laminar flow to turbulence flow .The improvement rate becomes clear at an angle of attack (12ο), it was noticed also that changing the position of the internal acoustic excitation on the outer surface of the profile to be near from the leading edge increases the lift coefficient. The increase rate becomes (28.5%) in lift coefficient for the slot position (6% chord) from the leading edge which is higher than the slot position (11.5% chord) from the leading edge for an angel of attack (12ο).

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