【发布时间】:2014-07-11 00:21:44
【问题描述】:
我目前正在设计一个程序,它将在 x 轴上输出 4 到 10 范围内的值的图形。但是,当我绘制图表时,它只绘制点而不是 For 循环中所需的 6 个点。有人可以帮忙解决这个问题吗?
我已附上我的代码和图表:
![% Inputs
R=0.4; % Radius of Rotor
B=3; % Number of blades
V=2; % Fluid velocity
Rho=998; % Fluid Density
N=9; % Number of Blade Elements
Cp_estimate=0.5; % Estimate power coefficient
Alpha_design=4; % Design alpha
Cl_design=1.04; % Design lift coefficient
% Variables
TSR=4; % Initial tip speed ratio
Cp=0; % Initial power coefficient
i=1; % Counter
alpha_new=0; % Initial value for alpha new
axial_induction=0; % Initial axial induction factor
tolerance=0.01; % Tolerance Value
Check=1; % Initial check value
axial_induction_old=0; % Initial value for old axial induction factor
for TSR=4:10,disp(TSR), % TSR from 4 to 10
while abs(Check)>=tolerance
r_local=\[(R./N)*1; (R./N)*2; (R./N)*3; (R./N)*4; (R./N)*5; (R./N)*6; (R./N)*7; (R./N)*8; (R./N)*9\];
r_over_R=r_local / R;
TSR_local=r_over_R .* TSR;
Phi=(2/3)*atan(1./TSR_local);
C=((8.*pi.*r_local) ./ (B.*Cl_design)).*(1-cos(Phi));
sigma=(B*C) ./ (pi.*r_local.*2);
Cl=\[1.3; 1.1; 1; 0.9; 0.86; 0.83; 0.8; 0.75; 0.5\]; % Lift Coefficients
Cd=\[0.027; 0.024; 0.02; 0.019; 0.018; 0.016; 0.013; 0.012; 0.01\]; % Drag Coefficients
axial_induction= 1 ./ (((4.*(sin(Phi).^2)) ./ (sigma.*Cl_design.*cos(Phi)))+1);
angular_induction= (1-(3*axial_induction)) ./ ((4.*axial_induction)-1);
axial_induction_old = axial_induction;
TSR_local = TSR*(r_local./R); % Local Tip Speed Ratio
Phi = (2/3)*atan(1./TSR_local); % Angle of Relative Fluid
relative_wind= atan((1-axial_induction) ./ ((1+axial_induction).*TSR));
F=(2/pi).*acos(exp(-(((B/2).*(1-(r_over_R))) ./ ((r_over_R).*sin(relative_wind))))); % Tip Loss Factor
C_T=(sigma.*((1-axial_induction).^2) .* ((Cl.*cos(relative_wind))+(Cd.*sin(relative_wind)))) ./ ((sin(relative_wind)).^2);
if C_T(:,i)<0.96
axial_induction=1 ./ (1+(4.*F.*(sin(relative_wind).^2)) ./ (sigma.*Cl.*cos(relative_wind)));
elseif C_T(:,i)>0.96
axial_induction=1 ./ (((4.*F.*cos(relative_wind)) ./ (sigma.*Cl))-1);
end
D=(8./(TSR.*N)).*(F.*(sin(Phi).^2).*(cos(Phi)-((TSR_local).*(sin(Phi)))).*(sin(Phi)+((TSR_local).*(cos(Phi)))).*(1-(Cd./Cl).*atan(Phi)).*(TSR_local.^2));
Cp=sum(D);
Diff=axial_induction-axial_induction_old;
Check=max(Diff(:));
end
store_Phi(:,TSR)=Phi;
store_TSR_local(:,TSR)=TSR_local;
store_axial_induction(:,TSR)=axial_induction;
store_angular_induction(:,TSR)=angular_induction;
store_relative_wind(:,TSR)=relative_wind;
store_Check(:,TSR)=Check;
store_Diff(:,TSR)=Diff;
store_Cp(:,TSR)=Cp;
store_TSR(:,TSR)=TSR;
end
figure(1)
plot(store_TSR,store_Cp)
hold all
title('Cp vs Tip Speed Ratio')
xlabel('TSR')
ylabel('Cp')][1]
【问题讨论】:
-
store_Cp 在循环结束时是什么样子的?它应该是一个长度为 10 的向量,但 plot 将忽略任何 NaN 值。但是,用第 4 个值初始化它应该将值 1-3 设置为零,因此它必须有一些非 NaN。但随后 store_TSR(1,[1:3]) 也将为零。
标签: matlab matrix graph matrix-multiplication