Simulation of unsteady fluid flow and heat transfer by BEM

Jure Ravnik (Avtor), Leopold Škerget (Avtor)

Povzetek

A boundary element method based solver for simulation of unsteady laminar viscous flow and heat transfer in three-dimensions has been developed. The algorithm solves the incompressible Navier- Stokes equations written in velocity-vorticity form and coupled with energy equation. Buoyancy is modelled within the Boussinesq approximation. The solver has recently been adapted for simulation of unsteady phenomena. The governing set of equations consists of the kinematics equation and transport equations for vorticity and temperature. Velocity and temperature boundary conditions are known, vorticity boundary conditions are calculated during the simulation by single domain BEM applied on the kinematics equation. The transport equations are solved by a domaindecomposition BEM approach, which yields sparse integral matrices and enables simulation using large computational grids. Rayleigh-Benard convection is used for a test case. In this case fluid is heated flow below, thus making it highly unstable. Already at low driving temperature of the bottom wall, the fluid becomes unstable. Vortices are formed above the hot bottom wall and travel up by buoyancy forces. Flow exhibits oscillatory behaviour, which at higher temperatures leads to chaotic and turbulent flow. The phenomenon was simulated using different driving temperatures of the bottom wall, observing the change of flow characteristics for steady to unsteady oscillatory regime and at even higher temperature to chaotic behaviour. Time series of heat flux and field functions were examined by phase portraits to determine the flow regime. A grid independence study and time step analysis was performed to asses the algorithms capability of simulation of unsteady behaviour.

Ključne besede

boundary element method;heat transfer;unsteady fluid flow;transport equations;

Podatki

Jezik:	Angleški jezik
Leto izida:	2011
Tipologija:	1.08 - Objavljeni znanstveni prispevek na konferenci
Organizacija:	UM FS - Fakulteta za strojništvo
UDK:	536
COBISS:	15314710
Št. ogledov:	1433
Št. prenosov:	24
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
URN:	URN:SI:UM:
Strani:	Str. 261-266
ID:	8718182