Accession Number : ADA097215


Title :   Finite Elements for Fluid Dynamics.


Descriptive Note : Final rept. 1 Jul 79-30 Jun 80,


Corporate Author : TEL-AVIV UNIV (ISRAEL) DEPT OF APPLIED MATHEMATICS


Personal Author(s) : Geffen,Nima


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA097215


Report Date : Aug 1980


Pagination or Media Count : 93


Abstract : The first two parts of this report wind up a few questions in the mathematical formulation of vector fields governed by conservation and rotationality laws, with explicit application to fluid dynamic fields, possibly with shock waves. The points treated have a strong bearing on computational schemes and the stability of numerical calculations and the results provide a priori information on the way to select the appropriate set of equations, the right functional, and the most promising approximation space for finite element discretizations. The last assertion is then tested for the tricomi equation in a nonuniformly elliptic domain. A mixed Tricomi problem is discretized by an alternative collocation scheme which proves to be acoustic and stable as demonstrated on a few test-cases. The collocation finite difference schemes have proven superior thus to the finite elements for this case. They are, however, more specialized and natural for linear problems and simple geometries. The variationally based finite elements, on the other hand, hold a better promise for complex geometries, and for an accurate treatment of shocks. (Author)


Descriptors :   *FINITE ELEMENT ANALYSIS , *FLUID DYNAMICS , ISRAEL , COMPUTATIONS , RANDOM VARIABLES , MATRICES(MATHEMATICS) , SHOCK WAVES , GRAPHS , APPROXIMATION(MATHEMATICS) , BOUNDARY VALUE PROBLEMS , LINEARITY , GEOMETRY , VECTOR SPACES


Subject Categories : Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE