Boundary layer effects on the vortex shedding in a Donaldson- type hydrofoil

27th IAHR Symposium on Hydraulic Machinery and Systems

Fontanals, A.^1,2 ; Guardo, A.^1,2 ; Zobeiri, A.^3 ; Egusquiza, E.^1 ; Farhat, M.^3 ; Avellan, F.^3

Centre de Diagnòstic Industrial i Fluidodinàmica, Universitat Politècnica de Catalunya BARCELONATECH(UPC-CDIF), Av. Diagonal 647, Barcelona

08028, Spain^1

Escola Universitaria d'Enginyeria Tècnica Industrial de Barcelona, Consorci Escola Industrial de Barcelona, Universitat Politècnica de Catalunya BARCELONATECH (UPC- EUETIB), C\ Compte d'Urgell, 187, Barcelona

08036, Spain^2

Laboratory for Hydraulic Machines, École Polytechnique Fédérate de Lausanne (EPFL- LMH), Av. de Cour 33 Bis, Lausanne

CH-1007, Switzerland^3

关键词: Boundary layer effects;    Boundary layer velocity;    Hydrodynamic forces;    Hydropower plants;    Laminar to turbulent transitions;    Machine structures;    Production flexibility;    Vortex shedding frequency;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/3/032045/pdf
DOI  :  10.1088/1755-1315/22/3/032045

来源: IOP

【 摘 要 】

Fluid - Structure Interaction (FSI) phenomena is becoming a relevant study field for the design or revamping of hydropower plants. The generalized trend of increasing flow rates and reducing rotor blades/stay vanes thickness in order to improve the efficiency of the machine together with a major push from plant owners/operators for production flexibility (partial load operation is more common nowadays) make the FSI between the vortex shedding phenomenon and the vanes/blades of the machine an area of interest. From a design point of view, the machine structure has to resist all the hydrodynamic forces generated and maintain tension stresses under the fatigue limit to ensure a machine lifetime of several decades. To accomplish that goal, designers have to assure there is no presence of strong coupling phenomena (lock-in) between the vortex shedding frequency and the eigenfrequencies of the structure. As the vortex street is directly related to the state of the boundary layer along the hydrofoil, in this paper the effect of the boundary layer on the vortex shedding in a Donaldson-type hydrofoil is studied using Computational Fluid Dynamics (CFD). The development of the boundary layer along the Donaldson trailing edge hydrofoil chord is presented under lock-off conditions. The results are validated against previously obtained experimental results. Since the Donaldson trailing edge is non-symmetric, the boundary layer velocity profiles are reported for the suction and pressure side of the hydrofoil. In addition, the effect of the Donaldson trailing edge on laminar-to-turbulent transition on both sides of the hydrofoil is studied.