KIT Computational Engineering Lab.

Research Theme
(H.NISHIDA's Lab.)

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Cartesian Grid Approach

Boundary Fitted Coordinate System

Cartesian Grid System

* Seamless Virtual Boundary Method:
Usually the boundary fitted coordinate (BFC) system is used for simulating the complicated flow field. On the other hand, in the virtual boundary method, the velocity condition, e.g., non-slip condition, is satisfied by adding the external forcing terms to the governing equations on the Cartesian grid.

Pressure Distributions of Flow around a Circular Cylinder

Overall View

Research on Environmental Simulation

* Numerical Simulation of Flow in Lake BIWA:
Lake BIWA is the largest lake in japan. In lake BIWA, there are about 460 inflow rivers and 1 outflow river (Seta river).

Pressure Distributions on November 1

Velocity Vectors on November 1

Higher Order Numerical Simulation

* DNS of Homogeneous Isotropic Turbulence:
Homogeneous isotropic turbulence is computed by using variable order method of lines with 8th order of spatial accuracy and 1024x1024x1024 grid resolution.

Time Evolution of Enstrophy Field

Development of Compressible Equations into Incompressible Flow Simulation

* DNS of Incompressible Turbulence Using Compressible Equations:
DNS of incompressible turbulence is executed by compressible Navier-Stokes equations with 10th order of spatial accuracy and 128x128x128 grid resolution.

Comparison of Enstrophy Field (red:compressible sol., blue:incompressible sol.)

Parallel Algorithm

* Massively Parallel Computation:
Variable order method of lines has very good parallel property on "Pilot-3 (64 processor elements)" system in Tsukuba University and "SSCMPP (256 processor elements)" system in JAEA.

Parallel Property on Pilot-3

Parallel Property on SSCMPP

Research on Velocity Correction of Incompressible Velocity Field

* Velocity Correction of Incompressible Velocity with Noises:
The velocity with noises is corrected by using spatial filter and Helmholtz's decomposition techniques.

Fundamental Velocity

Velocity with 10% Noises

Corrected Velocity Field