the unsteady free convection flow between two long vertical parallel plates withvariable temperature and mass diffusion in the presence of the thermal radiation hasbeen presented. the governing dimensionless coupled linear partial differentialequations on the flow are solved by using the laplace transform technique. theexact solutions have been obtained for the fluid velocity, temperature and t...

thermal resistance of the external walls of buildings is highly important for reducing and optimizing the energy consumption needed for heating and cooling the buildings. identifying and evaluation of the thermal performance of common external wall systems can be very effective in improving the heat resistance. the hollow clay- block system extremely are in use in the iran construction system, ...

in this research, the coupling between non-gray radiation and separation convection flow in a duct is investigated numerically. distributions of absorption coefficients across the spectrum  are obtained from the hitran2008 database. the full-spectrum k-distribution method is used to deal with the non-gray part of the problem, while the gray radiation calculations are performed using the planck ...

In this study, an analysis has been performed for free convection with radiation effect over a thermal forming nonlinearly stretching sheet. Parameters n, k0, Pr, G represent the dominance of the nonlinearly effect, radiation effect, heat transfer and free convection effects which have been presented in governing equations, respectively. The similarity transformation and the finite-difference m...

A theory for the electromagnetic radiation from unbalanced transmission lines is developed. It is shown that radiation results from the convection current that develops in unbalanced transmission lines where the resistances of the lines are unequal. The process that leads to the generation of the nonlinear convection current in unbalanced transmission lines is explained. It is proved that the c...

A numerical finite difference study has been earned out for two dimensional radiation-natural convection interaction phenomena in a vertical circular pin located at a non-participating (i.e. transparent) fluid. The coupled conservation equations in boundary layer (continuity, momentum, and energy equations) and pin energy equation are solved simultaneously using modified box method and fully im...

In the present work, an inverse analysis of combined radiation and laminar forced convection heat transfer in a two-dimensional channel with variable cross sections is performed. The conjugate gradient method is used to find the temperature distribution over the heater surface to satisfy the prescribed temperature and heat flux distributions over the design surface. The fluid is considered to b...

Infrared thermography was used to measure heat transfer by radiation and the surface temperature of starlings (Sturnus vulgaris) (N=4) flying in a wind tunnel at 6-14 m s-1 and at 15-25 degrees C. Heat transfer by forced convection was calculated from bird surface temperature and biophysical modelling of convective heat transfer coefficients. The legs, head and ventral brachial areas (under the...

We describe a relatively simple time-dependent convection model that can be coupled to the equations of radiation hydrodynamics. We show that it behaves in a physically plausible way in protostellar collapse flows and is quantitatively correct for nonlinear RR-Lyrae pulsations and the Sun. Together with the equations of radiation hydrodynamics the model closely approximates the classical stella...