Asymmetric vortices on a slender body of revolution

Zilliac, Gregory G.; Degani, David; Tobak, Murray

doi:10.2514/6.1990-388

Cited by 48 publications

(43 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tiny imperfections, even as small as the dust particles (approximately 3-µm diameter) incidentally coating the nose of the model, were found to change the direction and phase of the side force distribution in response to the roll angle change. The finding by Zilliac et al 5 implies that the leading-edge vortex genesis and subsequent growth are highly sensitive to small imperfections of the nose tip. In addition to the AOA and the roll angle, side force is also sensitive to other parameters, including nose fineness ratio, nose bluntness, nose geometry, Reynolds number, body slenderness, surface roughness, freestream turbulence, and so on.…”

Section: Nomenclaturementioning

confidence: 97%

“…With regard to the roll angle effect, a number of researchers have found that side force depended heavily on roll angle. 5,6 As AOA exceeded the vortex onset angle that generates side force, the variation of side force with respect to the roll angle altered from a continuous distribution to a square waveformlike distribution. 5 Zilliac et al 5 further examined the trends of side force variation vs nose roll angle.…”

Section: Nomenclaturementioning

confidence: 99%

“…5,6 As AOA exceeded the vortex onset angle that generates side force, the variation of side force with respect to the roll angle altered from a continuous distribution to a square waveformlike distribution. 5 Zilliac et al 5 further examined the trends of side force variation vs nose roll angle. Tiny imperfections, even as small as the dust particles (approximately 3-µm diameter) incidentally coating the nose of the model, were found to change the direction and phase of the side force distribution in response to the roll angle change.…”

Section: Nomenclaturementioning

confidence: 99%

See 2 more Smart Citations

Side Force Reduction of Cone-Cylinder Using Microballoon Array Actuator

Leu

Chang

2005

Journal of Propulsion and Power

View full text Add to dashboard Cite

The reduction of side force acting on a cone-cylinder slender body using a microballoon array actuator is examined. This microballoon array actuator can be inflated to a height of approximately 1.2 mm on the curve surfaces of the slender body. Experimental results indicate that side forces can be significantly reduced by inflating actuators near the weak and strong separated vortex structures. The mechanism of side force reduction has been investigated via both hot-wire and surface pressure measurements. Interestingly, unlike the conventional methods of changing the vortices from asymmetric to symmetric pairing for side force reduction, a microballoon array actuator makes vortices more asymmetric. It was found that two mechanisms can characterize the reduction of side force. The first mechanism involves that the weak side vortex lifts off prematurely because the microballoon actuation replaces the vortex pair structures with a more asymmetrically positioned pattern, enabling the formation of a new (third) vortex in the near-wall region. The second mechanism involves the strength of the newly generated (third) vortex being able to be effectively controlled via the microballoon actuation. Microballoon actuators can effectively alter the evolution of the new (third) near-wall vortex structure.

show abstract

Section: Nomenclaturementioning

confidence: 97%

Section: Nomenclaturementioning

confidence: 99%

Section: Nomenclaturementioning

confidence: 99%

See 1 more Smart Citation

Side Force Reduction of Cone-Cylinder Using Microballoon Array Actuator

Leu

Chang

2005

Journal of Propulsion and Power

View full text Add to dashboard Cite

show abstract

“…It is well known that the sign changes of side force are caused by the occurrences of additional vortex separated alternately from the port and starboard side of the body to the initial vortex pair originated from the body apex. [5][6][7] How the plasma actuations affect the asymmetric forces and vortex flow on the circular-cone forebody 4 at high angles of attack upto 70…”

Section: Introductionmentioning

confidence: 99%

“…7 As the angle of attack is increased, the vortex pair is lifted away from the body surface. The vortex which lies further away on a side of the body is detached from the body surface as angle of attack is further increased.…”

Section: Local Side Force Pressure Distribution and Flow Patternmentioning

confidence: 99%

Influence of Plasma Actuations on Forebody Side Forces and Wakes

Zhao

Gao

Liu

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

The variation of the asymmetric force and vortex wake on a 20• circular-cone forebody with angle of attack from 35• to 70• at zero sideslip are investigated. A pair of plasma actuators is designed and placed near the apex of the forebody. The pressure distributions over the forebody are measured in a low-turbulence 3.0 m × 1.6 m low-speed open-circuit wind tunnel at freestream velocity 5 m/s and Reynolds number of 50, 000 based on the cone base diameter. The pressure data are used to calculate the side force distribution along the forebody axis and to infer the salient features of the separated flow over the forebody under three modes of controls: plasma-off, plasma port-on and plasma starboard-on. Effects of the plasma actuations on vortex wake and side force over the cone forebody at angle of attack upto 70• are identified.

show abstract