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diff --git a/3765/CH1/EX1.7/Ex1_7.sce b/3765/CH1/EX1.7/Ex1_7.sce new file mode 100644 index 000000000..db4a9b507 --- /dev/null +++ b/3765/CH1/EX1.7/Ex1_7.sce @@ -0,0 +1,45 @@ +clc +// Example 1.7.py +// A flat plate with a chord length of 3 ft and an infinite span(perpendicular to +// the page in fig 1.5) is immersed in a Mach 2 flow at standard sea level +// conditions at an angle of attack of 10 degrees. The pressure distribution +// over the plate is as follows: upper surface, p2=constant=1132 lb/ft^2 lower +// surface, p3=constant=3568 lb/ft^2. The local shear stress is given by tau_w = +// 13/xeta^0.2, where tau_w is in pounds per square feet and xeta is the distance +// in feet along the plate from the leading edge. Assume the distribution of +// tau_w over the top and bottom surfaces is the same. Both the pressure and +// shear disributions are sketched qualitatively in fig. 1.5. Calculate the lift +// and drag per unit span on the plate. + +// + +// Variable declaration +M1 = 2.0 // mach number freestream +p1 = 2116.0 // pressure at sea level (in lb/ft^2) +l = 3.0 // chord of plate (in ft) +alpha = 10.0 // angle of attack in degrees + +p2 = 1132.0 // pressure on the upper surface (in lb/ft^2) +p3 = 3568.0 // pressure on the lower surface (in lb/ft^2) + +// Calculations + +// assuming unit span + +pds = -p2*l + p3*l // integral p.ds from leading edge to trailing edge (in lb/ft) + +L = pds*cos(alpha*%pi/180.0) // lift per unit span (in lb/ft), alpha is converted to radians + +Dw = pds*sin(alpha*%pi/180.0) // pressure drag per unit span (in lb/ft), alpha is converted to radians + +Df = 16.25 * (l** 4.0/5.0) // skin friction drag per unit span (in lb/ft) + // from integral tau.d(xeta) + +Df = 2 * Df * cos(alpha*%pi/180.0) // since skin friction acts on both the side + +D = Df + Dw // total drag per unit span (in lb/ft) +// Result +printf("\n Total Lift per unit span = %.0f lb", L) + +printf("\n Total Drag per unit span = %.0f lb", D) + |