blob: 19bfc2bdabba79720d44b108a4198bdcb6c4e176 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
clc; funcprot(0);
//Example 10.10 Ground Effect
// Initialisation of variables
alp = 10; //True angle of attack
c = 6;
b = 36;
V = 100; // Free stream velocity
rho = 0.002387;
Cl = 1.07; //From fig 8.8
Cd = 0.077; //From fig 8.8
z = 4; // Height above ground
gap = 2*z;
// Calculations
S = c*b;
L = Cl*(rho/2)*S*V^2;
D = Cd*(rho/2)*S*V^2;
gapBYspan = gap/S;
sigma = 0.46; // From fig 8.10
EMAR = (b^2/S)/(1-sigma);
alpG = alp - (-5); //Effective geometric angle of attack for clark Y after sutracting zero lift angle.
a = alpG - 18.25*(1/c -1/EMAR) //Angle of attack measured from angle of zero lift for Cl = 1.07.
m = Cl/a; // Slope of lift curve
Cl_g = alpG*m // Lift Coefficient taking ground under consideration
L_g = Cl_g*(rho/2)*S*V^2 ; //Lift taking ground under consideration
Cd = 0.090; //From figure 8.8 for Cl = 1.19
Cd_g = Cd - (Cl^2/%pi)*(1/c -1/EMAR); // Lift Coefficient taking ground under consideration
D_g = Cd_g*(rho/2)*S*V^2 ; //Drag taking ground under consideration
//Results
disp(D,"Drag when ground is neglected (lb) :", L,"Lift when ground is neglected (lb) :" );
disp(D_g,"Drag when ground is considered (lb) :", L_g,"Lift when ground is considered (lb) :" );
|
