Improving rowing performance by adjusting oar blade size and angle

The principal aim of the work presented here is to investigate and demonstrate that a forward tilted rowing blade would result in a more efficient and effective motion of the blade through the water that would result in a higher boat speed when an equal input power is provided. A 1:5 scaled rowing boat is used to determine the performance of...

Drag Force on a Starting Plate Scales with the Square Root of Acceleration

We report results on the instantaneous drag force on plates that are accelerated in a direction normal to the plate surface, which show that this force scales with the square root of the acceleration. This is associated with the generation and advection of vorticity at the plate surface. A new scaling law is presented for the drag force on...

Turbulent flow and friction in a pipe with repeated rectangular ribs

Measurements were conducted in the fully developed turbulent flow in a pipe with internal diameter D at a Reynolds number of Re _D= 1.6 × 10 ⁵ . The pipe walls were equipped with regularly spaced square ribs of relative height h/ D= 0.154 , while the pitch-to-roughness height was varied between p/ h= 1.67 and p/ h= 6.67 ....

Investigation on the drag force and flow field of an accelerating plate

We present results on the instantaneous drag force acting on a rectangular plate that accelerates in a direction normal to the plate surface. Conventionally the drag force on an accelerating object is divided into a steady state term and an added mass term, which can both be time-dependent. However, for prolonged accelerations this theory...

Hydrodynamics of rowing propulsion

This paper presents the results of the time resolved flow field measurements around a realistic rowing oar blade that moves along a realistic path through water. To the authors' knowledge no prior account of this complex flow field has been given. Simultaneously with the flow field measurements, the hydrodynamic forces acting on the blade...

PIV applied to a moving rowing blade

We investigate the fluid motion generated by a moving rowing blade. The blade follows a complex path with rather strong acceleration and subsequent deceleration. The blade path is mimicked at a 1:2 scale in a large open-top water tank using a robot system. The tank is transparent, thus enabling full optical access for performing large-field...

Towards determination of power loss at a rowing blade: Validation of a new method to estimate blade force characteristics

To analyze on-water rowing performance, a valid determination of the power loss due to the generation of propulsion is required. This power los can be calculated as the dot product of the net water force vector ( ^~ F _w;o ) and the time derivative of the position vector of the point at the blade where ^~ F <sub...

Drag force on an accelerating submerged plate

We present results on the drag on, and the flow field around, a submerged rectangular normal flat plate, which is uniformly accelerated to a constant target velocity along a straight path. The plate aspect ratio is chosen to be to resemble an oar blade in (competitive) rowing, the sport which inspired this study. The plate depth, i.e. the...

Experimental velocity study of non-Boussinesq Rayleigh-Bénard convection

Natural convection driven heat transfer in fluids with strongly variable properties: A particle image velocimetry study

The High Performance Light Water Reactor (HPLWR) is one of the six innovative nuclear energy systems proposed by the Generation IV International Forum. The use of water at supercritical pressure as the coolant in the HPLWR allows a significative increase of the thermal efficiency of the power plant, a reduction in size and complexity of the...