2026-04-17T15:42:40Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/3852582026-01-29T01:57:30Zcom_2072_1033col_2072_452950

Thermal contraction of the boundary layer from progressive cooling and its possible use as active flow control technique Arias Montenegro, Francisco Javier Heras Jiménez, Salvador Augusto de las Universitat Politècnica de Catalunya. Departament de Mecànica de Fluids Universitat Politècnica de Catalunya. SIC - Sistemes Intel·ligents de Control Àrees temàtiques de la UPC::Física::Física de fluids Fluid dynamics Unsteady flow (Fluid dynamics) Boundary layer Boundary layer re-attachment Active flow control Dinàmica de fluids Flux de transició (Dinàmica de fluids) In this work, consideration is given to thermal contraction of the boundary layer from the progressive cooling of the airfoil and its possible technological use as an active flow control technique. Here, it is thought that if the airfoil is progressively cooled from the leading-edge toward the trailing-edge the increase in density will translate into a progressive contraction of the boundary layer which eventually could be used as technique for either re-attachment or delay detachment of the boundary layer. Utilizing the von Karman momentum integral an analytical expression for the reduction of the thickness of the boundary layer by thermal contraction was derived which predicts contractions around 10 percent for temperatures drops around 50° K. Experimental measurements made on a heated flat plate with controlled thermal gradient agree with the theoretical prediction within a 10 per cent. The possibility of prompt contraction of the boundary layer by condensation (of the air or its moisture content) if the temperature drops below the subcooling temperature, is an open question which should be addressed in future research Postprint (author's final draft) 2023-06-01 Article Arias, F.J.; De Las Heras, S.A. Thermal contraction of the boundary layer from progressive cooling and its possible use as active flow control technique. "International journal of thermal sciences", Juny 2023, vol. 188, article 108244. 1290-0729 https://hdl.handle.net/2117/385258 10.1016/j.ijthermalsci.2023.108244 eng https://www.sciencedirect.com/science/article/abs/pii/S1290072923001059 http://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access Attribution-NonCommercial-NoDerivatives 4.0 International application/pdf