Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

nal design did not perform as well as expected in model-scale, wind-tunnel testing. The object of this project was to determine
why and develop a reliable tool to be used for an improved design. Predictions were done for the inlet operating in the presence
of a ground plane (runway) with a crosswind at zero forward speed, a critical design point for inlet operation. The Wind Navier-
Stokes code was used with structured Chimera grids having about five million grid points and divided into 30 to 40 zones. Fine
grid calculations used 30 processors. The computations were made using the NAS SGI Origin computing cluster. Analysis predictions
agreed with data, predicting the onset of separation and the details of the flow field for attached and separated flows, including
the effects of the ground vortex. The analysis proved capable of predicting the influence of the wind-tunnel walls on the measured
flow field. Part of the effort was directed at determining grid topology and density requirements and identifying the best procedure
for running the code. A process has been developed that can provide flow prediction results in several days for a new design. Predictions
correspond well with experiment, but additional test cases are needed to increase confidence in the procedure.
Author
Computational Fluid Dynamics; Inlet Flow; Navier-Stokes Equation; Parallel Processing (Computers); Structured Grids (Mathematics);
Engine Inlets
20000064614 NASA Ames Research Center, Moffett Field, CA USA
Fast Particle Methods for Multiscale Phenomena Simulations
Koumoutsakos, P., NASA Ames Research Center, USA; Wray, A., NASA Ames Research Center, USA; Shariff, K., NASA Ames
Research Center, USA; Pohorille, Andrew, NASA Ames Research Center, USA; Welcome to the NASA High Performance Computing
and Communications Computational Aerosciences (CAS) Workshop 2000; February 2000; In English; See also
20000064579; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document
We are developing particle methods oriented at improving computational modeling capabilities of multiscale physical phenomena
in : (i) high Reynolds number unsteady vortical flows, (ii) particle laden and interfacial flows, (iii)molecular dynamics
studies of nanoscale droplets and studies of the structure, functions, and evolution of the earliest living cell. The unifying computational
approach involves particle methods implemented in parallel computer architectures. The inherent adaptivity, robustness
and efficiency of particle methods makes them a multidisciplinary computational tool capable of bridging the gap of micro-scale
and continuum flow simulations. Using efficient tree data structures, multipole expansion algorithms, and improved particle-grid
interpolation, particle methods allow for simulations using millions of computational elements, making possible the resolution
of a wide range of length and time scales of these important physical phenomena.The current challenges in these simulations are
in : [i] the proper formulation of particle methods in the molecular and continuous level for the discretization of the governing
equations [ii] the resolution of the wide range of time and length scales governing the phenomena under investigation. [iii] the
minimization of numerical artifacts that may interfere with the physics of the systems under consideration. [iv] the parallelization
of processes such as tree traversal and grid-particle interpolations We are conducting simulations using vortex methods, molecular
dynamics and smooth particle hydrodynamics, exploiting their unifying concepts such as : the solution of the N-body problem
in parallel computers, highly accurate particle-particle and grid-particle interpolations, parallel FFT’s and the formulation of processes
such as diffusion in the context of particle methods. This approach enables us to transcend among seemingly unrelated areas
of research.
Author
Computer Techniques; Data Structures; Parallel Computers; Computerized Simulation; Particles
20000064696 Sverdrup Technology, Inc., Huntsville, AL USA
Interfacing the Generalized Fluid System Simulation Program with the SINDA/G Thermal Program
Schallhorn, Paul, Sverdrup Technology, Inc., USA; Palmiter, Christopher, Sverdrup Technology, Inc., USA; Farmer, Jeffery,
NASA Marshall Space Flight Center, USA; Lycans, Randall, Sverdrup Technology, Inc., USA; Tiller, Bruce, NASA Marshall
Space Flight Center, USA; [2000]; 13p; In English; 34th; 34th Thermophysics Conference, 19-22 Jun. 2000, Denver, CO, USA
Contract(s)/Grant(s): NAS8-40386; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
A general purpose, one dimensional fluid flow code has been interfaced with the thermal analysis program SINDA/G. The
flow code, GFSSP, is capable of analyzing steady state and transient flow in a complex network. The flow code is capable of modeling
several physical phenomena including compressibility effects, phase changes, body forces (such as gravity and centrifugal)
and mixture thermodynamics for multiple species. The addition of GFSSP to SINDA/G provides a significant improvement in
convective heat transfer modeling for SINDA/G. The interface development was conducted in two phases. This paper describes
the first (which allows for steady and quasi-steady - unsteady solid, steady fluid - conjugate heat transfer modeling). The second
(full transient conjugate heat transfer modeling) phase of the interface development will be addressed in a later paper. Phase 1
development has been benchmarked to an analytical solution with excellent agreement. Additional test cases for each develop-
82