Blade Element Theory for Wind Turbines - Small Wind Turbines: Analysis, Design, and Application - page 49

function simple_power_calc(Numb)

% Program to implement blade element/one-dimensional wake
%analysis for a horizontal-axis wind turbine with any number of
%blades of any length. Unless otherwise specified, all lengths are
%normalised by the tip radius (r_tip) and all velocities by the wind
%speed, U0. In this version the blade element width (delr) is equal
%for all blade elements.

% Function argument is:
% Numb - number of blades

% Main variables are:
% a - axial interference factor
% adash - rotational interference factor
% aoa - angle of attack of blade element
% chord - chord of blade element
% C_a - factor for elemental thrust
% C_adash - factor for elemental torque
% Cd - drag coefficient
% Cl - lift coefficient
% Cp - power coefficient
% Ct - thrust coefficient
% delr - radial width of blade element
% delthr - thrust on blade element
% deltor - torque on blade element
% lambda - tip speed ratio (TSR)
% lamr - local speed ratio of blade element, Eq. (3.7b)
% gam - circulation of blade element
% nbes - number of blade elements
% phi - inflow angle between Ut and plane of rotation
% Re - blade element Reynolds number
% r_hub - radius of hub
% r_tip - radius of tip (m)
% rad - radius of midpoint of blade element
% sigma - local solidity, Eq. (3.14)
% twist - angle between chord line and plane of rotation
% Ut - effective velocity at blade element, Eq. (3.7a)
% U0 - wind speed (m/s)
visc = 1.5e-5; % Kinematic viscosity of air (m^2/s)
rho = 1.2; % Density of air (kg/m^3)
tol = 1.e-4; % Convergence tolerance for BE analysis
in = load('rad_ch_tw.dat'); % data file with radius, chord, and twist
rad=in(:,1); % Recover the radius of the blade elements
nbes = rad(1); % First entry is nbes