The effect of radiation on transient natural convection past a doubly infinite plate
نویسنده
چکیده
The present research note is concerned with the transient (short time) simultaneous free convection and radiation analysis of a viscous fluid along a doubly infinite vertical isothermal flat plate. To simplify a very complicated problem, an incompressible flow field is used in the analysis. Generally, the exact numerical solution of this problem is quite lengthy. However, by considering an optically thick radiating gas, expressed by the Rosseland diffusion approximation, the solution is much simpler. Moreover, this case leads to a complete similarity transformation of the governing partial differential equations into a set of ordinary differential equations. An exact numerical solution is obtained of the resulting ordinary differential equations for a Prandtl number equal to 0.733 and for a wide range of involved parameters. Der Einflufi der Strahlung auf transiente freie Konvektion iiings einer unendlichen Platte Zusammenfassung. Der vorliegende Bericht befal3t sich mit der Untersuchung der transienten Vorg~inge bei gleichzeitiger freier Konvektion und Strahlung an einem z~hen Fluid entlang einer unendlichen isothermen ebenen Platte. Um das komplizierte Problem zu vereinfachen, wird eine inkompressible Str6mung angenommen. Normalerweise ist die exakte numerische L6sung dieses Problems sehr langwierig. Beriicksichtigt man jedoch ein optisch dichtes, strahlendes Gas wie es durch die Rosselandsche Diffusionsn~iherung ausgedriickt wird, ist die LSsung wesentlich einfacher. Zudem fiihrt dieser Fall zu einer kompletten )khnlichkeitstransformation der beschreibenden partiel!en Differentialgleichungen in einen Satz von gew6hnlichen Differentialgleichungen. Eine exakte numerische L6sung wird erzielt ftir eine PrandtlZahl yon 0.733 und einem groBen Bereich der beteiligten Parameter.
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