The impact of skinsuit zigzag tape turbulators on speed skating performance

At the 1998 Nagano Winter Olympic Games, zigzag tape was introduced on the race suit lower legs and cap of speed skaters. Application of these zigzag devices on live skaters and cylinders in the wind tunnel showed large improvements in the aerodynamic drag. These wind-tunnel results were unfortunately not widely published, and the impact of...

On the Cyclist's Drag Crisis

The distribution of the critical velocity (point of minimum aerodynamic drag) is determined along the body of a time-trial cyclist by flow measurement in the model's near-wake.

Base Drag Reduction of Heavy Duty Vehicles by Combining a Tail and Guide Vanes: A Numerical and Experimental Analysis

To limit the threat posed by global climate change it is vital to reduce the emissions of the transport sector in the short term. Two existing aerodynamic add-on devices for the rear-end of a heavy duty vehicle, a tail and guide vanes, are combined in an attempt to achieve a larger drag reduction. A research is performed using numerical...

Aerodynamic drag determination of a full-scale cyclist mannequin from largescale PTV measurements

Large-scale Particle Tracking Velocimetry (PTV) measurements are cond ucted in the wake of a fu ll-scale cyclist model in time-trial position at freestream velocities between 12.5 and 15 m/ s, corresponding to Reynolds numbers of the order of 5×105. Lagrangian particle tracking is employed to determine the velocity and static pressure statistics...

Aerodynamic investigation of the near wake flow topology on a two-man bobsleigh

Drag measurements on bluff-bodies such as bobsleighs using force balance systems have been in prevalence for a few decades. However these studies do not reveal anything on the flow behaviour around the body. In the recent past, various flow visualization techniques have been applied to investigate the flow behaviour around bobsleighs. Even...

Aerodynamics of transiting objects via large-scale PIV - the Ring of Fire Concept

A novel measurement system, the Ring of Fire, is deployed which enables the aerodynamic drag estimation of transiting cyclists. The system relies upon the use of large-scale stereoscopic PIV and the conservation of momentum within a control volume in a frame of reference moving with the athlete. The rider cycles at a velocity of approximately 8...

Aerodynamic drag of a transiting sphere by large-scale tomographic-PIV

A method is introduced to measure the aerodynamic drag of moving objects such as ground vehicles or athletes in speed sports. Experiments are conducted as proof-of-concept that yield the aerodynamic drag of a sphere towed through a square duct in stagnant air. The drag force is evaluated using large-scale tomographic PIV and invoking the time...

SAMID, an interactive system for aircraft drag minimization studies. Mathematical models and methods

An interactive computer program system has been developed that can be used in aircraft drag minimization studies. It comprises algorithms for choosing the spanwise distributions of lift, pitching moment, chord and thicknessto-chord ratio of lifting elements. The choices are optimal in that they minimize induced plus viscous drag while satisfying...

ARSPNSC: A method to calculate subsonic steady and unsteady potential flow about complex configurations

A new method ARSPSC is described for the calculation of steady and time-linearized unsteady subsonic potential flow about complex 2-D and 3-D configurations. The method belongs to the category of the so-called panel methods. Applications have been made to a 2-D oscillating flat plate, a 2-D multi-component airfoil with oscillating flap and a 3-D...

An ALGOL-program for the calculation of incompressible three-dimensional turbulent boundary layers

A computer program has been prepared for the calculation of turbulent boundary layer development, based on a 3-D version of the turbulent energy method. The method is briefly discussed. The computer program is described in detail. The present program is restricted to developable surfaces.