Unsteady partial cavitation can cause damage to hydraulic machinery and understanding it requires knowledge of the basic physics involved. This paper presents main results a research program based on wall-pressure measurements aimed at studying unsteadiness in cavitation. Several features have been pointed out. For cavity lengths that did not exceed half foil chord was stated be stable. At closure peak pressure fluctuations recorded originating from local region frequency depending length....

The present work was carried out in the scope of a numerical-experimental collaborative research program, whose main objective is to understand mechanisms instabilities partial cavitating flow. Experiments were conducted configuration rectangular foil located cavitation tunnel. Partial investigated by multipoint wall-pressure measurements together with lift and drag numerical videos. computations on two-dimensional hydrofoil section are based single fluid model cavitation: liquid/vapor...

The objective of this work is to present combined numerical and experimental studies natural flow-induced vibrations flexible hydrofoils. focus on identifying the dependence foil’s vibration frequencies damping characteristics inflow velocity, angle attack, solid-to-fluid added mass ratio. Experimental results are shown for a cantilevered polyacetate (POM) hydrofoil tested in cavitation tunnel at French Naval Academy Research Institute (IRENav). foil observed primarily behave as chordwise...

For numerical simulations of cavitating flows, many physical models are currently used. One approach is the void fraction transport equation‐based model including source terms for vaporization and condensation processes. Various have been proposed by different researchers. However, they tested only in flow configurations, which make direct comparisons between results difficult. A comparative study, based on expression as a function pressure, presented present paper. This analytical...

This paper presents comparisons between two-dimensional (2D) CFD simulations and experimental investigations of the cavitating flow around a symmetrical 2D hydrofoil. configuration was proposed as test case in “Workshop on physical models tools for computation flows” at 5th International Symposium cavitation, which held Osaka November 2003. The calculations were carried out ENSTA laboratory (Palaiseau, France), visualizations measurements performed IRENav cavitation tunnel (Brest, France)....

This paper presents an original experimental study concerning the structural response of a flexible lightweight hydrofoil undergoing various flow conditions including partial cavitating flow. It is based on analysis static deformation, vibrations, strains, and stresses polyacetal NACA0015 cantilevered in hydrodynamic tunnel, at Reynolds numbers ranging from 3 × 105 to 6 105. A specific distance measurement laser device was developed measure deformation hydrofoil. The vibration measured by...

Vertical axis turbines, also called Darrieus present interesting characteristics for offshore wind and tidal applications but suffer from vibrations a lower efficiency than the more conventional horizontal turbines. The use of variable pitch, in order to control angle attack blades continuously during their rotation, is considered this study overcome these problems. 2D blade-resolved unsteady Reynolds-Averaged Navier–Stokes (RANS) simulations are employed evaluate performance improvement...

_ In this paper, the hydroelastic response of a NACA0015 composite hydrofoil is studied experimentally and numerically. The foil made materials with fibers not aligned span foil, which results in occurence bend-twist coupling material. Computations are performed using partitioned approach. flow problem solved boundary element method. structural modelled two different finite models. first one, 2D shell 3D solid elements second model, 1D beam elements. experiments conducted an open circulation...

Abstract The hydro-elastic response of a flexible NACA 0015 hydrofoil is investigated for both wetted and cavitating flow conditions. Computational fluid dynamics (CFD) analysis are performed using fully implicit coupling between the ISIS-CFD solver (developed by METHRIC team at Ecole Centrale de-Nantes) modal approach structure. Reynolds-averaged Navier–Stokes (RANS) first validated conditions around similar rigid hydrofoil, with experimental results carried out hydrodynamic tunnel French...

Cavitation inception and development on a two-dimensional foil with an Eppler E817 cross section issued from inverse calculus have been experimentally investigated. The is theoretically designed to wide cavitation-free bucket allowing large range of angle incidence (Eppler, R., 1990, Airfoil Design Data, Springer-Verlag, Berlin). cavitation numbers, the noise level, velocity distribution, minimum pressure coefficient, patterns (bubble, leading edge “band type” cavitation, attached sheet...

The present paper is concerned with the numerical and experimental investigation of hydroelastic behavior a deformable hydrofoil in uniform flow. study developed within general framework marine structure design sizing. An setup IRENav hydrodynamic tunnel which cambered rectangular mounted. image-processing device enables visualization foil displacement. As for part, problem solved finite element method, while fluid volume method using two distinct codes that are coupled through an iterative...