Columnar vortex generator for flow control over a ski-jump ramp

Abstract

Purpose Aircraft carriers are essential for modern naval operations. Takeoff maneuver is critical because of the short runway distance. The ski-jump ramp is a system which increases the angle of attack of the aircraft, so an extra lift is obtained. Regarding the flow configuration over the ski-jump ramp at ahead wind conditions, the complex aerodynamic environment generated by the ramp configuration influences aircraft operations. This flow field is mainly characterized by a low velocity recirculation bubble that reduces aircraft performances. The purpose of this paper is to find a solution to reduce these adverse effects, by means of flow control devices, which opens a wide field of research. Design/methodology/approach This paper presents wind tunnel tests performed to study the flow configuration in the vicinity of the ski-jump ramp and the flow control devices effects. A 1:100 scaled ship model was built to develop experimental tests by using flow control devices fabricated by means of additive manufacturing. Particle image velocimetry technique was used to measure the velocity flow field and the turbulence intensity maps. Findings Interesting results were obtained when the angle between the intersection of the ski-jump ramp and the columnar vortex generator (CVG) is modified. The results showed a high reduction of the recirculation bubble generated over the flight deck. Originality/value CVG has presented encouraging results as a passive flow control device. A study of the variation of CVG geometrical parameters has been developed.

Field test and numerical reconstitution of natural winds at the tunnel entrance section of high-speed railway

“…The standard 32 m-span simply supported girder bridge is established in the TBDC model, which is applied most frequently in highspeed railway bridges in China. The atmospheric domain at the tunnel exit is simulated (Bardera et al, 2018;Kulak et al, 2018). Four types of boundary conditions are applied in the CFD model, including velocity-inlet, no-slip wall, symmetry and pressure-outlet.…”

“…The atmospheric domain at the tunnel exit is simulated using 200 × 120 × 50 m and 200 × 120 × 50 m cuboids in the TBDC and TF infrastructure, respectively. A rigid body velocity of 250 km/h is given to the HSRT by compiling a UDF into ANSYS/Fluent (Bardera et al , 2018; Kulak et al , 2018). Four types of boundary conditions are applied in the CFD model, including velocity-inlet, no-slip wall, symmetry and pressure-outlet.…”

Insight into the factors affecting the safety of take-off and landing of the ship-borne helicopter

“…Czerwiec 67 LHA Bow-flap Shafer 64 DDG-81 Porous surfaces, different fence, and blowing Landman 68 LHD Flap and columnar vortex generator (CVG) Findlay 69 DDG-81 Eleven different configurations of fences Greenwell 70 SFS Eight different configurations of inclined screen Kääriä 71 SRF Different side-flap configurations and hangar notch Forrest 65,66 SFS2 Five different modifications including chamfer, flap, tabs, saw-tooth, and cylinder Kääriä 72 SRF Side-flap and hangar notch Kääriä 1 SRF Six windward hangar side-face modifications Mora 73 SFS Four configurations with different hangar roof curvature Mora 74 SFS Active plasma flow control technique with two configurations Bardera 75 Aircraft carrier Cylinder, triangular-notched fence and CVG Bardera 76 Aircraft carrier Different configurations of flat plate, cylinder, and CVG Bardera 77 Aircraft carrier CVG with two angles Matias 78 SFS2 Trapezoidal vortex generator, suction, and blowing Bardera 79 Aircraft carrier CVGs with five spiral parameters one rotor diameter. For medium-weight helicopters, it is usually around 30 m. The NORSTOCK Standard C-004 for the offshore helicopter 83 puts forward the similar requirements to CAP 437.…”

Effects of uniform injection and suction through perforated pentagonal cylinders on the flow and heat transfer

“…Thus, to reduce the fluctuating forces and eliminate the vortex shedding behind bluff bodies, various passive and active flow-control methods are used. Passive flow control methods are composed of the modification of the geometrical configurations or attaching extra devices such as sinusoidal front and rear faces, splitter plate, control plates and rods, a grooved wall or tripwire, changing surface roughness, columnar vortex generator and cavitation slot control (Darekar and Sherwin, 2001; Hwang and Yang, 2007; Hangan and Kim, 2003; Shukla et al , 2009; Bao and Tao, 2013; Zhu and Yao, 2015; Bardera et al , 2018; Liu et al , 2019). On the other hand, the active flow control methods are applied to the bluff body using energy input without modifying the geometrical configuration.…”