Environmental Engineering Reference
In-Depth Information
rad(1) = []; % Remove from array for radius
chord=in(:,2); % recover the chord of the blade elements
r_tip= chord(1); % First entry is r_tip
chord(1) = [];
twist=in(:,3); % Recover the twist of the blade elements
r_hub = twist(1); % First entry is r_hub
twist(1) = [];
delr=rad(2)-rad(1); % Determine width of blade elements
out_format=' %7.4f %3d %7.2f %7.3f %7.3f %8.5f'… ' %8.5f %8.3e \n';
U0 = 100.0;
while U0 > 0.0
U0 = input(' Enter the wind speed in m/s: end with -ve: ');
if U0 < 0.0, break; end
while U0 > 0.0
lambda = input(' Enter TSR: end with -ve: ');
if lambda < 0.0, break; end
thrust = 0.0; torque = 0.0;
fprintf('\n')
fprintf(' Radius iter. aoa a Cl Cd')
fprintf(' deltor Re \n')
a = 0.3; % Initialise a
for i = 1: nbes % Loop over each blade element
adash = 0.0; deltor = 0.0;
lamr = lambda*rad(i); % Local speed ratio, Eq. (3.7b)
sigma = 0.5*Numb*chord(i)/pi/rad(i); % Local solidity
diffa = 200*tol*a;
while diffa > tol*a
phi = atan((1 - a)/(1 + adash)/lamr) ; Eq.(3.12)
cosphi = cos(phi);
sinphi = sin(phi);
aoa = phi*180.0/pi - twist(i);Eq.(3.8)
Ut = sqrt((1-a)*(1-a) + (lamr*(1 + adash))^2);
Re = Ut*U0*chord(i)*r_tip/visc ; % Reynolds number
[Cl, Cd] = LandD_0012(aoa, Re); % Find Cl and Cd
C_a = Cl*cosphi + Cd*sinphi; % For axial force
C_adash = Cl*sinphi - Cd*cosphi; % tangential force
% Balance axial momentum and blade thrust, Eq. (3.13), to find
% new a
faca = Ut*Ut*sigma*C_a;
% Use Glauertès empirical correction when a > 0.5, Eq. (2.20)
if faca > 1.0
 
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