Computation of pressures on under-water-bodies

An existing code in the division is utilized to obtain pressures on under-water-bodies supplied by the User agency (Naval Science and Technology, Vishakapatnam - 6

Super-linear speed-up of a parallel multigrid Navier-Stokes solver on Flosolver

In parallel computing, scalability is an important issue and getting linear speed-ups is difficult for most codes. Super-linear speed up has been achieved on an eight-processor Flosolver system for a multigrid Navier-Stokes code. The physical problem solved, the parallelization method, the speed-ups obtained and possible explanations for this result are discussed here

Smoothening of airfoil coordinates

In this paper a smoothening procedure based on Garabedian13; Algorithm is presented. This method is assessed by studying the smoothness of the curvature variation obtained against the changes made to the original profile

Calculation of axisymmetric transonic small perturbation equation using conservative scheme

Transonic flows past axisymmetrical bodies have been computed using Conservative difference schemes. Comparison of calculations with available experimental results show that in many cases the present conservative calculations are closer to experimental results. This finding is contrary to the pouplar opinion that nonconservative schemes are uniformly superior to the conservative schemes regarding experimental agreement. As available accounts on conservative differencing and artificial viscosity are rather terse, an expository account ofthese has been presented in the report. In particular, practical details of implementing conservative schemes for solving TSP equation have been given. It may be mentioned that because of its discrete nature conservative differencing is delicate and consequently, given a finite difference discretisation the work that needs to be done to decide whether the given differencing is conservative or not has been given in detail. Role of artificial viscosity in admitting compression shocks has been discussed and a way of obtaining such a scheme is given with all the details

Processing element selector for Flosolver Mk3

Flosolver Mk3 [1-2] consists of five single board computers based on the Intel 1860 RISC processor. One of the processor is the host and has the UNIX operating system. Other processing elements (PE) have only system debug monitor (iSDM) which permits limited access to disc. The debug monitor is used for the initial set up of PE's and debugging during program execution. The design given in this report shares a single display terminal among PE's for initial set up debugging

Scalability of the parallel GCM-T89 code

The factors governing the scalability' of parallelization13; of the GCM-T80 code, operational at NCMRWF, are13; examined quantitatively. Aspects missed in earlier13; Indian implementations are discussed. Finally, results13; of a new hybrid strategy are presented showing13; significant improvement of parallel efficiency13

An iterative scheme for numerical solution of transonic small perturbation equation

Computational aspects of Transonic Small Perturbation (TSP) equation are studied. The TSP equation is a consistent approximation of comparable Euler Equations with the sole restriction of small perturbation. A new algorithm for solving conservative discretization of TSP equation is presented. Unconditional stability of the scheme was shown and a number of computational experiments were carried out which demonstrate the ruggedness of the scheme. Despite the TSP equation, though not valid near the blunt leading edge, a large number of calculations in the literature have been made for flow past airfoils like NACA 0012 using TSP equation. Handling of boundary13; condition in the numerical calculation tends to be ad-hoc near the leading edge. It is shown that if the leading edge slope is integrable a satisfactory analysis can be carried out. Numerical calculations confirm the usefullness of the approach. (Author

On boundary condition for transonic small perturbation equation for body having blunt leading edge

A method for handling boundary condition for TSP calculation for body having blunt leading edge is presented which removes the adhoc method of handling it in the literature

Flosolver Mk1B - An eight processor parallel machine

The Flosolver MklB has two nodes, each having four processing elements based on intel's 8086/8087 chips. In each node one of the processor acts as the host. The internade communication is done through the parallel ports available on the hosts. Within a node the cynchronisation and inter processor communication is done through the global memory. As a sample case the flow part NACA 0012 aerofoil at zero incident using transonic small perturbation equation is computed and an efficiency of 90 percent is obtained

16-processor Flosolver

Flosolver is a parallel computer built at the National13; Aeronautical Laboratory (NAL), Bangalore. 16 Processor13; Flosolver system at NAL has four nodes each having four13; processors of Intel 80386/80387. Nodes are connected using13; parallel interface .Many application codes including Panel13; code, Monsoon code, Transonic flow calculation etc. are13; operational on this syste