Aerodynamics of smooth and rough square-section prisms at incidence in very high Reynolds-number cross-flows

Abstract The aerodynamics of smooth and slightly rough prisms with square cross-sections and sharp edges is investigated through wind tunnel experiments. Mean and fluctuating forces, the mean pitch moment, Strouhal numbers, the mean surface pressures and the mean wake profiles in the mid-span cross-section of the prism are recorded simultaneously for Reynolds numbers between 1 $$\times$$ × 10 $$^{5}$$ 5 $$\le$$ ≤ Re $$_{D}$$ D $$\le$$ ≤ 1 $$\times$$ × 10 $$^{7}$$ 7 . For the smooth prism with $$k_s$$ k s / D = 4 $$\times$$ × 10 $$^{-5}$$ - 5 , tests were performed at three angles of incidence, i.e. $$\alpha$$ α = 0 $$^{\circ }$$ ∘ , −22.5 $$^{\circ }$$ ∘ and −45 $$^{\circ }$$ ∘ , whereas only both “symmetric” angles were studied for its slightly rough counterpart with $$k_s$$ k s / D = 1 $$\times$$ × 10 $$^{-3}$$ - 3 . First-time experimental proof is given that, within the accuracy of the data, no significant variation with Reynolds number occurs for all mean and fluctuating aerodynamic coefficients of smooth square prisms up to Reynolds numbers as high as