Vol.3, No 15, 2003 pp.1007-1015
UDC 532
Invited Paper
UNIVERSAL EQUATIONS OF UNSTEADY MHD INCOMPRESSIBLE
FLUID FLOW WITH VARIABLE
ELECTRO-CONDUCTIVITY ON HEATED MOVING PLATE
Zoran Boričić, Dragiša Nikodijević,
Dragica Milenković, Živojin Stamenković
Faculty of Mechanical Engineering, University of Nis
Aleksandra Medvedeva 14, 18000 Nis, Serbia and Montenegro
Tel.: (+381) 18 524 915, Fax: (+381) 18 524 930, E-mail: dragisan@masfak.ni.ac.yu
Abstract. The laminar, unsteady flow of viscous incompressible fluid
caused by moving of semi-infinite flat plate with variable velocity is
considered in this paper. The electro-conductivity is assumed as the linear
function of velocities ratio. The present external magnetic field is perpendicular
to the plate. The fluid properties, except the electro-conductivity, are
isotropic and constant. The plate is warmed up (cool down). Dissipation
and Joule heat are neglected. For the investigation of described problem
the method of "universalisation" is used which has been formulated by L.G.Lojcijanski
for boundary layer problems. The universal equations of described problem
have been obtained by using this method. The momentum equation of problem
is introduced firstly, in order to obtain the universal equations of the
described problem. The approximate universal equations of mentioned problem
are also given in the paper.
Key words: MHD incompressible fluid flow, universal equations,
general similarity method.
UNIVERZALNE JEDNAČINE NESTACIONARNOG
MHD STRUJANJA NESTIŠLJIVOG FLUIDA PROMENLJIVE
ELEKTROPROVODNOSTI NA ZAGREJANOJ PLOČI
U radu se razmatra laminarno, nestacionarno strujanje, viskoznog, nestišljivog
fluida izazvanog kretanjem ravne ploče, promenljivom brzinom. Pretpostavlja
se da je elektroprovodnost fluida linearna funkcija odnosa brzina. Prisutno
je spoljašnje magnetno polje koje je upravno na ploču. Sve karakteristike
fluida, osim elektroprovodnosti su izotropne i konstantne. Ploča je zagrejana
(hlađena). Disipacija i Džulova toplota se zanemaruju. Za razmatranje opisanog
problema primenjuje se metoda "univerzalizacije" jednačina laminarnog graničnog
sloja koju je formulisao L.G. Lojcijanski. Univerzalne jednačine ovog problema
su dobijene korišćenjem opisane metode. Pri dobijanju jednačina najpre
se uvodi impulsna jednačina opisanog problema. Pridbližne univerzalne jednačine,
za dato strujanje takođe su date u ovom radu.
