Wall-shear stress measurements of turbulent flow over ribbed surfaces using the micro-pillar shear stress sensor MPS3

The drag reduction effect of a semi-circular riblet-structured surface in a turbulent boundary layer is experimentally investigated using the micro-pillar shear stress sensor MPS3. The MPS3 sensor is a novel tool for the quantitative measurement of the wall-shear stress distribution and possesses a high spatial and temporal resolution. The...

Tomographic particle-image velocimetry measurements in a turbulent wavy channel flow

To investigate small scale turbulent structures and their statistical properties in non-isotropic turbulent flow subjected to favorable and adverse pressure gradients, a novel method to divide the instantaneous flow field into strictly monotonic elements is applied to tomographic particle-image velocimetry data.Especially the scaling regimes of...

Time-Resolved stereoscopic PIV measurements of cyclic variations in an internal combustion engine

The flow field during the intake and the compression stroke of an optical four-stroke, four-valve, single-cylinder gasoline type demonstrator engine is measured using time-resolved stereoscopic particle-image velocimetry (PIV) to analyze these flow structures. The flow is measured in the tumble plane at an engine speed of 1500 rpm in 50...

Tomographic particle-image velocimetry in an IC engine

The flow structures during the intake and compression phase within the cylinder of an internal combustion(IC)engine strongly influence the mixing and combustion process. To gain a better understanding of the flow field, fully three-dimensional quantitative measurement techniques have to be applied to the flow field. Analog off-axis holographic...

Experimental investigation of turbulent boundary layer flow undergoing spanwise traveling transversal surface waves

The influence of spanwise traveling transversal surface waves on the near-wall flow field of turbulent boundary layers with and without adverse pressure gradient is investigated by particle-image velocimetry (PIV) and micro-particle tracking velocimetry (μ-PTV). A detailed analysis of the velocity profile immediately downstream of the actuated...