Euler-Lagrange coupling for porous parachute canopy analysis

We apply a new Euler-Lagrange coupling method to 3-D parachute problems, which generally involve fluid-structure interactions between a flexible, elastic, porous parachute canopy and a high-speed airflow. The method presented couples an Arbitrary Lagrange Euler formulation for the fluid dynamics and an updated Lagrangian finite element formulation for the parachute canopy. The Euler-Lagrange coupling handles fluid-structure interaction without matching the fluid and structure meshes. In order to take account of the effect of the parachute permeability, this coupling computes interaction forces based on the Ergun porous flow model. This paper provides validations for the technique when considering parachute applications and discusses the interest of this development to the parachute designer

Fluid Structure Interaction for Hydraulic Problems

Fluid Structure interaction plays an important role in engineering applications. Physical phenomena such as flow induced vibration in nuclear industry, fuel sloshing tank in automotive industry or rotor stator interaction in turbo machinery, can lead to structure deformation and sometimes to failure. In order to solve fluid structure interaction problems, the majority of numerical tests consists in using two different codes to separately solve pressure of the fluid and structural displacements. In this paper, a unique code with an ALE formulation approach is used to implicitly calculate the pressure of an incompressible fluid applied to the structure. The development of the ALE method as well as the coupling in a computational structural dynamic code, allows to solve more large industrial problems related to fluid structure coupling

Interaction Fluide-Structure pour les problèmes de dynamique rapide

National audienceLa dynamique rapide regroupe des phénomènes physiques en grande déformation de courte durée impliquant généralement un fluide et une structure. Le crash, le développement d’un airbag, le tossage d’un navire sont autant d’exemples d’interaction fluide-structure spectaculaires de l’ordre de quelques millisecondes. La simulation numérique a beaucoup apporté à la compréhension de ces phénomènes physiques. Cependant la complexité des simulations numériques actuelles, en dynamique rapide, conduit encore à des problèmes liés au temps de calcul et implicitement aux maillages utilisés pour décrire les géométries. Les grandes déformations impliquent un traitement spécial du maillage. Certaines approches s’affranchissent de la connectivité comme la méthode SPH. D’autres remaillent le domaine de calcul. Ici nous nous intéresserons à la formulation ALE (Arbitrary Lagrange Euler) et, à titre d’illustration, nous l’appliquerons à l’impact hydrodynamique d’un dièdre

Air blast reflecting on a rigid cylinder: simulation and reduced scale experiments

International audienceIn this paper, the Multi-Material ALE formulation is applied to simulate the propagation of an air blast through the atmosphere, and its reflection on an assumed rigid cylindrical obstacle. The mathematical and numerical implementations of this formulation are presented. In order to validate the formulation and prove its ability to capture the propagation and reflection of high pressure waves, comparisons of the simulations with the experimental blast pressure measured on an assumed rigid cylinder are performed. The simulation conducted via the presented models and methods gives good predictions for pressure time histories recorded on the rigid cylinder