Generalized Porous Media Flow in ICFD-LSDYNA: FSI, Free-Surface, RTM and Parachute Modeling

RODRIGO R. PAZ; FACUNDO DEL PIN; INAKI CALDICHOURY; HUGO G. CASTRO

Salzburg

Conferencia; 11 th European LS-DYNA Conference 2017; 2017

Large industries, engineering companies and academia have needs that constantly evolve, requiring models capable to accurately describe problems with increasing complexity. In this regard, the coupling of multiple fields representing different physical models (or phenomena) is of vital importance in these industries and it must be seriously observed by scientist, engineers and developers of well-established numerical codes, like LS-DYNA. Physical and engineering processes involving fluid flows through free and porous mediums are present in a wide range of these kind of problems.In the ground vehicles industry, understanding aerodynamics phenomena allows us to optimize the operation of a wide spectrum of road vehicles, that ranges from road passenger transport (cars, buses, trains) to road commercial transport (trucks and trains). Road vehicle aerodynamics is acomplex topic due to the interaction between the air flow and the ground and some parts (that play an important role in drag and lift development) could be treated as a porous media (e.g. the radiator, the condenser, air filters, etc). Industries like aerospace and those related to oil production have increased their trustfulness on numerical models and codes for the design, research, production and verification of highly critical parts and production processes. Most of these industries have adopted manufacturing procedures involving composites materials in liquid state, like the High Pressure Resin Transfer Molding (HP-RTM) methods, where a Newtonian (or Non-Newtonian) fluid flows through highly anisotropic matrices filling an initially empty container.Parachute deploying and flight is another example in which the coupling of several fields is needed in order to describe its dynamics and evaluate different designs. This case, where a stream of an incompressible fluid flows through a thin and deformable porous fabric, represents a challengingproblem from the numerical point of view that can be tackled considering a strong fluid-structure interaction (FSI) strategy.This article reviews the numerical modeling of flows through general anisotropic porous media in LS-DYNA and introduces new aspects when considering FSI problems. A generalization of the Navier-Stokes equations that will allow the definition of sub-domains with different permeability/porosity is used. The SUPG|OSS stabilizing Finite Element Method for the spatial approximation and the second-order Fractional Step Method for the time integration were adopted. Also, the paper will provide some examples showing the use of LS-DYNA in a wide range FSI problems. Details about how the users´ interface looks like will be given at the conference talk (it also can be found in the LS-DYNA users manual).