LS-DYNA includes three new solvers for multiphysic purposes :
- Incompressible CFD (ICFD)
- Electromagnetics (EM)
- CESE/ Compressible CFD and Chemistry
Pursuing LSTC's objective of offering a unified simulation environment for an always wider range of applications, those three new solvers are automatically included and available for any registered DYNA user (starting from R7, double precision executables only).
The adoption of new materials in the design of lighter and more fuel efficient cars and the introduction of movable parts for active aerodynamic control create new challenges to the traditional model of separated CFD/structural mechanics departments in the automotive industry. New structural materials may exhibit unpredictable behaviors under flow loads and temperatures at road test conditions.
It is LSTC's belief that fully coupled thermal/structural/CFD simulations will become increasingly necessary to avoid last minute surprises in the design chain. LS-DYNA offers a simple solution to incorporate the structural model into the CFD analysis using some of the most state of the art Finite element technology applied to fluid mechanics. The ICFD solver can run as a stand alone for pure CFD applications (the study of drag lift around bluff body and vehicles for example), or be coupled to the thermal and structural mechanical problems for linear and non-linear complex FSI and conjugate heat transfer applications. It also makes use of an automatic mesh generator for the fluid volume thus greatly reducing the cost of setting up the model. For more details, please refer to the associated menu links.
The Electromagnetism solver solves the Maxwell equations in the Eddy current (induction-diffusion) approximation. This is suitable for cases where the propagation of electromagnetic waves in air (or vacuum) can be considered as instantaneous. Therefore, the wave propagation is not solved. The main applications are magnetic metal forming or welding, induced heating, and so forth. The EM module allows the introduction of a source of electrical current into solid conductors and the computation of the associated magnetic field, electric field, as well as induced currents. The EM solver is coupled with the structural mechanics solver (the Lorentz forces are added to the mechanics equations of motion), and with the structural thermal solver (the ohmic heating is added to the thermal solver as an extra source of heat). The EM fields are solved using a Finite Element Method (FEM) for the conductors and a Boundary Element Method (BEM) for the surrounding air/insulators. Thus no air mesh is necessary. For more details, please refer to the associated menu links.
CESE/ Compressible CFD
The CESE solver is a compressible flow solver based upon the Conservation Element/Solution Element (CE/SE) method, originally proposed by Dr. Chang in NASA Glenn Research Center. This method is a novel numerical framework for conservation laws. It has many non-traditional features, including a unified treatment of space and time, the introduction of conservation element (CE) and solution element (SE), and a novel shock capturing strategy without using a Riemann solver. To date, this method has been used to solve many different types of flow problems, such as detonation waves, shock/acoustic wave interaction, cavitating flows, and chemical reaction flows. In LS-DYNA, it has been extended to also solve fluid-structure interaction problems with the embedded (or immersed) boundary approach or moving (or fitting) mesh approach. For more details, please refer to the associated menu links.