Measurments of laminar mixed convection flows adjacent to an inclined surface

Measurements of laminar mixed forced and free convection air flow adjacent to an upward and a downward facing, isothermal, heated inclined surface (at 45 degrees) are reported. Local Nusselt numbers and the velocity and temperature distributions are presented for both the buoyancy assisting and the buoyancy opposing flow cases for a range of buoyancy parameters chi greater than zero but no more than 5 (chi = Gr sub x/Re sub x squared). The measurements are in good agreement with predictions which define a laminar mixed convection regime for buoyancy assisting flows as chi is greater than 0.1 but less than 7, and for buoyancy opposing flows as chi is greater than 0.06 but less than 0.25 for this incliation angle of 45 degrees. Simple mixed convection correlations for the local and average Nusselt numbers for inclined surfaces are also presented and they agree very well with predicted results. As expected, the local Nusselt number increases with increasing buoyancy parameter for assisting flows and decreases for opposing flows. For a given buoyancy parameter and Reynolds number, a downward facing surface provides essentially the same Nusselt number as the upward facing surface for the conditions examined in the experiment.