TY - JOUR

T1 - Axisymmetric stagnation-point flow and heat transfer of a viscous fluid on a moving plate with time-dependent axial velocity and uniform transpiration

AU - Jafari, Mohammad

AU - Bradaran Rahimi, Asghar

PY - 2013/2/1

Y1 - 2013/2/1

N2 - The unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite moving plate with transpiration W0 are investigated when the axial velocity and wall temperature vary arbitrarily with time. The free stream is steady and with a strain rate of a. An exact solution of the Navier–Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by the use of appropriate transformations for the most general case when the transpiration rate is also time-dependent, but results are presented only for uniform values of this quantity. The general self-similar solution is obtained when the axial velocity of the plate and its wall temperature vary as specified time-dependent functions. For completeness, sample semi-similar solutions of the unsteady Navier–Stokes equations have been obtained numerically using a finite difference scheme. All the solutions above are presented for different values of dimensionless transpiration rate, S = W0/√ aυ, where υ is the kinematic viscosity of the fluid. The effects of the sundry parameters, including transpiration rate, Prandtl number, oscillation frequency and accelerating/decelerating parameter, on the velocity and temperature profiles, as well as surface shear stresses and heat transfer coefficient, are investigated and results are shown through graphs.

AB - The unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite moving plate with transpiration W0 are investigated when the axial velocity and wall temperature vary arbitrarily with time. The free stream is steady and with a strain rate of a. An exact solution of the Navier–Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by the use of appropriate transformations for the most general case when the transpiration rate is also time-dependent, but results are presented only for uniform values of this quantity. The general self-similar solution is obtained when the axial velocity of the plate and its wall temperature vary as specified time-dependent functions. For completeness, sample semi-similar solutions of the unsteady Navier–Stokes equations have been obtained numerically using a finite difference scheme. All the solutions above are presented for different values of dimensionless transpiration rate, S = W0/√ aυ, where υ is the kinematic viscosity of the fluid. The effects of the sundry parameters, including transpiration rate, Prandtl number, oscillation frequency and accelerating/decelerating parameter, on the velocity and temperature profiles, as well as surface shear stresses and heat transfer coefficient, are investigated and results are shown through graphs.

KW - Stagnation flow

KW - Viscous fluid

KW - Exact solution

KW - Time-dependent axial movement

KW - Time-dependent heat transfer

KW - Transpiration

UR - https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878038222&doi=10.1016%2fj.scient.2012.12.010&partnerID=40&md5=97fba34d12e57d6b8a32de7de01a48a4

U2 - 10.1016/j.scient.2012.12.010

DO - 10.1016/j.scient.2012.12.010

M3 - Article

VL - 20

SP - 152

EP - 161

JO - Scientia Iranica

JF - Scientia Iranica

SN - 1026-3098

IS - 1

ER -