Reattaching Flow Behind a Square Bar Investigated with Temperature-Sensitive Paint

Flow visualizations of a square bump were conducted by means of Temperature-Sensitive Paint (TSP) in the Laminarwasserkanal of the IAG (University Stuttgart). In the investigation laminar, transitional and turbulent reattachment of the flow is investigated with the Reynolds number Rekk spanning 127 ≤ Rekk ≤ 1898. The variation of flow separation, flow reattachment and impinging flow structures are well captured with the TSP technique. The TSP technique requires a temperature difference between model surface and flow, therefore a thin TSP-Element was especially designed to electrically heat the surface. At low Reynolds numbers the non-adiabatic wall causes significant buoyancy forces leading to constraints of the useful working range with TSP in the Laminarwasserkanal. The location shift of flow reattachment and the variation of the impinging flow structures to characterize the flow will be shown in the final paper. Furthermore, the influence of the temperature difference between model surface and fluid, which is required for the TSP method, will be addressed, especially for low Rekk at low flow speed.