Infrared based visualization of wall shear stress distributions with a high temporal and spatial resolution

Abstract

These images are the result of a new infrared based measurement technique which allows the visualization of wall shear stress distributions with a high spatial and temporal resolution*. The experiments were conducted for the flow around a wall mounted cylinder with a height to diameter ratio of H/D = 2 for a Reynolds-Number of 40000 Re = D . The technique is not only able to capture the characteristic flow features displayed in figure 1, but can also visualize the unsteady processes in the wake of the cylinder with a good temporal resolution (Fig. 2)**.

A wall shear stress measurement technique using the thermal wakes of small heated spots

“…In addition to these quantitative techniques, a variety of qualitative, shear stress visualizing techniques have emerged in recent years, e.g. references [4] to [7]. These techniques take advantage of the fact that changes in the surface temperature are dependent on the near wall flow and the state of the flow (attached, separated, laminar, or turbulent).…”