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The present work is devoted to simulation of fluid-structure interaction and flow-induced vibration problems by using a partitioned procedure. A finite element structure solver is coupled with a finite volume fluid solver. A coupling interface has been developed for grid interpolation and scheme coupling control. An alternative mesh motion to a classical ALE formulation is proposed for the fluid computation and the method is validated by means of a test-case involving a pipe conveying fluid.

In order to make substantial progress in reducing the environmental impact of aircraft, a key technology is the reduction of aircraft weight. This challenge requires the development and the assessment of new technologies and methodologies of load prediction and control. To achieve the investigation of the specific case of gust load, ONERA defined a dedicated research program based on both wind tunnel test campaigns and high fidelity simulations.To reach the experimental objectives, a set-up was designed, manufactured and implemented within the ONERA S3Ch transonic wind tunnel facility. The first component, called gust generator, consists of two oscillating airfoils installed upstream of the wind tunnel test section and allows to produce air flow deflections. The second component, the test model, is a two degrees-of-freedom aeroelastic model of a supercritical airfoil. A test campaign has been performed leading to the generation of databases for high fidelity tools validation.These databases have been used in order to assess the capabilities of the elsA code (ONERA-Airbus-Safran property) using its aeroelastic module and a gust model based on the Field Velocity Method. A validation process has been defined in order to move from experimental results obtained in the wind tunnel with wall boundaries to industrial modeling computed with farfield boundaries. The full process was applied to a transonic case with sine gust excitation signals.

Cet article est consacréà la simulation numérique, par couplage externe de codes, de vibrations de structures flexibles induites parécoulements. Une revue des développements réalisés sur les deux codes disciplinaires mis en oeuvre est tout d'abord présentée, puis une application au cas d'un tube flexible soumis a unécoulement interne pour de petits déplacements et unécoulement laminaire est proposée. Mots clés : Interaction fluide-structure / couplage de codes externes / départ en instabilité / formulation ALE / structure flexible Abstract -Numerical simulation of a pipe conveying fluid. The present work is devoted to numerical simulation of flow induced vibrations by means of a partitioned code coupling procedure. First, fluid and structure codes are presented. Then the computation of a pipe conveying fluid for small displacement and laminar flow is investigated.

Hypothetical Small Break Loss Of Coolant Accident is identified as one of the most severe transients leading to a potential huge Pressurized Thermal Shock on the Reactor Pressure Vessel (RPV). This may result in two-phase flow configurations in the cold legs, according to the operating conditions, and to reliably assess the RPV wall integrity, advanced two-phase flow simulations are required. Related needs in development and/or validation of these advanced models are important, and the ongoing TOPFLOW-PTS experimental program was designed to provide a well documented data base to meet these needs. This paper focuses on pre-test NEPTUNE_CFD simulations of TOPFLOW-PTS experiments; these simulations were performed to (i) help in the definition of the test matrix and test procedure, and (ii) check the presence of the different key physical phenomena at the mock-up scale.