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

2018 ◽  
Vol 28 (5) ◽  
pp. 1156-1168 ◽  
Author(s):  
Rafael Bardera ◽  
Marina León-Calero ◽  
Joaquín de Nova-Trigueros
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Vortex Generator ◽  
Geometrical Parameters ◽  
Recirculation Bubble ◽  
Content Type ◽  
Flow Configuration ◽  
Columnar Vortex ◽  
Flow Control Devices ◽  
Control Devices

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.

Three-dimensional characterization of passive flow control devices over an aircraft carrier ski-jump ramp

2017 ◽  
Vol 232 (15) ◽  
pp. 2737-2744
Author(s):  
R Bardera ◽  
A Rodríguez-Sevillano ◽  
M León-Calero ◽  
J Nova-Trigueros
Keyword(s):  
Flow Control ◽  
Three Dimensional ◽  
Vortex Generator ◽  
Geometrical Parameters ◽  
Aircraft Carrier ◽  
Recirculation Bubble ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Flow Disturbances

The aircraft carrier is a key element in modern navies. On-board operations at sea take place under very severe conditions, which affect the aerodynamic flow on the flight deck. The ski-jump ramp is a curved runway that enables the aircraft to take-off using shorter runway distance. However, this geometry generates strong flow disturbances, mainly characterized by a recirculation bubble at the forward end of the ramp. This phenomenon reduces the aircraft performances and increases the pilot’s workload due to the unsteady forces which appear on the control surfaces. Passive flow control appears as a solution to this problem. Wind tunnel experimental research was developed in this study to mitigate the adverse aerodynamic effects of the ski-jump ramp presence. Different devices were tested using particle image velocimetry. Geometrical parameters of the devices were varied to study the effectiveness and select the best solution. Interesting results were found for the columnar vortex generator configurations. The optimum configuration could be applied shortly to the full-scale problem to reduce the adverse aerodynamic effects during take-off maneuvers.

Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Flat Plate ◽  
Vortex Structure ◽  
Film Cooling ◽  
Pressure Probe ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Cooling Hole ◽  
Control Devices

This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D laser Doppler velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a taller FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line.

Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance

2013 ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Flat Plate ◽  
Vortex Structure ◽  
Film Cooling ◽  
Pressure Probe ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Cooling Hole ◽  
Control Devices

This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D Laser Doppler Velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a higher FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line.

Optimizing of Flow Control Devices in a Single Strand Continuous Casting Tundish

2011 ◽  
Vol 284-286 ◽  
pp. 1209-1215 ◽  
Author(s):  
Lei Lei Zhang ◽  
Deng Fu Chen ◽  
Qiang Liu ◽  
Min Zhang ◽  
Xin Xie ◽  
...  
Keyword(s):  
Flow Field ◽  
Continuous Casting ◽  
Flow Control ◽  
Control Device ◽  
Flow Control Devices ◽  
Flow Control Device ◽  
Continuous Casting Tundish ◽  
Control Devices ◽  
Water Simulation ◽  
Orthogonal Optimization

Flow control devices (weir and dam) in a continuous casting tundish are very important to the flow field, which influences the temperature uniform and the inclusion floating. In this work, the weir and dam were firstly optimized through numerical simulation and water simulation synthetically by orthogonal optimization tests. And the optimal parameters showed that the distance from upper weir to inlet was 1000 mm, the distance of upper weir to tundish bottom was 150 mm, the distance from upper weir to dam was 600 mm, and the height of the dam was 320 mm. Then the effect of different arrangement holes on the dam was discussed through RTD curve and velocity field under the optimum flow control device. And it revealed that the hole influenced the flow pattern in that area obviously, a dam with two holes could get a better flow field.

scholarly journals Prediction of flow-control devices' noise with modified acoustic perturbation equations

2020 ◽  
Vol 22 (3) ◽  
pp. 619-627
Author(s):  
Luca Fenini ◽  
Stefano Malavasi
Keyword(s):  
Flow Control ◽  
Fluid Dynamic ◽  
International Standards ◽  
The Other ◽  
Computational Time ◽  
Noise Prediction ◽  
Acoustic Perturbation ◽  
Flow Control Devices ◽  
Control Devices ◽  
Perturbation Equations

Abstract Fluid-dynamic noise emissions produced by flow-control devices inside ducts are a concerning issue for valve manufacturers and pipeline management. This work proposes a modified formulation of Acoustic Perturbation Equations (APE) that is applicable to industrial frameworks where the interest is addressed to noise prediction according to international standards. This formulation is derived from a literature APE system removing two terms allowing for a computational time reduction of about 20%. The physical contribution of the removed terms is discussed according to the literature. The modified APE are applied to the prediction of the noise emitted by an orifice. The reliability of the new APE system is evaluated by comparing the Sound Pressure Level (SPL) and the acoustic pressure with the ones returned by LES and literature APE. The new formulation agrees with the other methods far from the orifice: moving over nine diameters downstream of the trailing edge, the SPL is in accordance with the other models. Since international standards characterize control devices with the noise measured 1 m downstream of them, the modified APE formulation provides reliable and faster noise prediction for those devices with outlet diameter, d, such that 9d < 1 m.

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