Research at DLR Göttingen on bluff body aerodynamics, drag reduction by wake ventilation and active flow control

Grosche, F.-R.; Meier, G. E. A.

doi:10.1016/s0167-6105(01)00161-1

Cited by 40 publications

(15 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A full-scale DSA350 pantograph was measured in a wind tunnel by means of acoustic mirror techniques [79]. Strong noise sources were identified at the foot, the panhead and the knee joint.…”

Section: Methodsmentioning

confidence: 99%

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Thompson

Iglesias

Liu

et al. 2015

International Journal of Rail Transportation

117

View full text Add to dashboard Cite

At speeds above 300-350 km/h, the main source of noise from trains is the aerodynamic noise caused by the air flow over the train structure. The sound level increases with train speed at a rate of between 60 and 80 times the logarithm of the speed so that, as speeds increase further, the noise increases dramatically. The main aerodynamic noise is produced by the air flow passing over the pantograph, the train nose, the bogie region and cavities such as the pantograph recess and the inter-coach gap. Experimental and numerical methods for studying aerodynamic noise are reviewed including the use of microphone arrays, wind tunnels, computational fluid dynamics and semi-empirical methods. Potential mitigation measures that can control aerodynamic noise are also reviewed.

show abstract

“…A full-scale DSA350 pantograph was measured in a wind tunnel by means of acoustic mirror techniques [79]. Strong noise sources were identified at the foot, the panhead and the knee joint.…”

Section: Methodsmentioning

confidence: 99%

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Thompson

Iglesias

Liu

et al. 2015

International Journal of Rail Transportation

117

View full text Add to dashboard Cite

show abstract

“…There they concluded that the vortex formation process is increasingly two-dimensional when the body is close to the wall. There have been several studies on the wake structure and aerodynamic drag reduction for vehicle-like bodies [9,19]. Those studies and the references there-in provide several results based on either PIV measurement or direct computation of three-dimensional Navier-Stokes equations with k-" turbulence model.…”

Section: Discussionmentioning

confidence: 99%

“…The vortex shedding of longitudinal edges on the afterbody is the major source of aerodynamics drag for a vehicle-like body [9]. The vortex shedding and downforce are in uenced by the boundary layer along the ground.…”

Section: Introductionmentioning

confidence: 99%

Vortex shedding from a square cylinder in presence of a moving wall

Bhattacharyya

Maiti

2005

Numerical Methods in Fluids

View full text Add to dashboard Cite

SUMMARYA numerical study on the ow past a square cylinder placed parallel to a wall, which is moving at the speed of the far ÿeld has been made. Flow has been investigated in the laminar Reynolds number (based on the cylinder length) range. We have studied the ow ÿeld for di erent values of the cylinder to wall separation length. The governing unsteady Navier-Stokes equations are discretized through the ÿnite volume method on a staggered grid system. A SIMPLE type of algorithm has been used to compute the discretized equations iteratively. A shear layer of negative vortex generates along the surface of the wall, which in uences the vortex shedding behind the cylinder. The ow-ÿeld is distinct from the ow in presence of a stationary wall. An alternate vortex shedding occurs for all values of gap height in the unsteady regime of the ow. The strong positive vortex pushes the negative vortex upwards in the wake. The gap ow in the undersurface of the cylinder is strong and the velocity proÿle overshoots. The cylinder experiences a downward force for certain values of the Reynolds number and gap height. The drag and lift are higher at lower values of the Reynolds number.

show abstract

“…It is assumed that the diffuser exhaust (station 3) will not influence the static pressure in the bluff body wake. The experimental data provided by Grosche24 and Georgiou25 indicate that such an interaction is indeed possible.…”

Section: The One‐dimensional Analysismentioning

confidence: 92%

Grounding and the influence of the total pressure losses in ducted wind turbines

Georgiou

Theodoropoulos

2009

Wind Energy

View full text Add to dashboard Cite

Ducted wind turbines are known to exceed the Betz limit for the power that may be extracted from free currents per unit cross-sectional area of their rotors. The present study points to another advantage: the fact that the turbine rotor (and the associated subassemblies) need not be lifted up on the air and rotated to align with the wind. They can function just as effectively by installing them on the ground and sucking air inside it. The analysis evaluates the effi ciency of a ducted wind turbine plant, exhausting into the wake of a bluff body, under both ideal and realistic component performance. The results indicate that there exists a strong need to develop diffusers with a very low loss coeffi cient (e.g. by employing suction or transpiration techniques). Under such conditions and by employing the above exhaust assist techniques, the ducted wind turbine concept may deliver effi ciencies more than an order of magnitude larger than those of the conventional plants.

show abstract

Research at DLR Göttingen on bluff body aerodynamics, drag reduction by wake ventilation and active flow control

Cited by 40 publications

References 8 publications

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Vortex shedding from a square cylinder in presence of a moving wall

Grounding and the influence of the total pressure losses in ducted wind turbines

Contact Info

Product

Resources

About