Error in Plotting The Surface graph.

clc
clear all
close all
%% Aircraft Parameters
b= 222.6664;   %ft
l=247.9163;   % ft
S=6200;       %ft^2
CR=45.4165;    %ft
CT=15.332;     %ft
AR=7.3;
TR=0.34;
lamda= 25; %degree
W=650000;   %pound
mach=0.77;
sound_speed=967.52;   %in feet/sec
density=5.87; % in slug/ft^3
cruise_weight=650000; %in pounds


%% Wake model

b_red=(3.14/4)*b;
velocity=mach*sound_speed;
Circulation=cruise_weight/(velocity*density*b_red);
y=-0.3*b:9:0.1*b;
z=-0.3*b:9:0.1*b;
[y,z]=meshgrid(y,z);
x=2*b +zeros(10,10);
rc=5;

% %%upwash_avg
syms s
chord_length=((2*S)/(b*(1+TR))*(1-(1-TR)*(2*s)/b));
right_wing=(Circulation/(4*3.14))*((y+s)./( (y+s).^2+ z.^2 + rc.^2)).*(1+(x./sqrt(x.^2+(y+s).^2+z.^2)))*chord_length;
left_wing=(Circulation/(4*3.14))*((y+b+s)./( (y+b+s).^2+ z.^2 + rc.^2)).*(1+(x./sqrt(x.^2+(y+b+s).^2+z.^2)));
I = (1/b)*((left_wing+right_wing)*chord_length);
qwe=int(I,s,0,b);
surf( y/b,z/b,qwe)

%%Error is Showing

Error using matlab.graphics.chart.primitive.Surface

Invalid parameter/value pair arguments.

Error in surf (line 145)

hh = matlab.graphics.chart.primitive.Surface(allargs{:});

Error in research_ff (line 38)

surf( y/b,z/b,qwe)

>>

Answer 1

[Walter Roberson]

qwe=int(I,s,0,b);

That is symbolic

surf( y/b,z/b,qwe)

surf cannot handle symbolic arguments, even if the symbols could be fully approximated as double.

You need to double(qwe) if it does not contain any free variables after integrating. If it contains free variables then fsurf()

[Walter Roberson]

clc
clear all
close all
%% Aircraft Parameters
b= 222.6664;   %ft
l=247.9163;   % ft
S=6200;       %ft^2
CR=45.4165;    %ft
CT=15.332;     %ft
AR=7.3;
TR=0.34;
lamda= 25; %degree
W=650000;   %pound
mach=0.77;
sound_speed=967.52;   %in feet/sec
density=5.87; % in slug/ft^3
cruise_weight=650000; %in pounds


%% Wake model

b_red=(3.14/4)*b;
velocity=mach*sound_speed;
Circulation=cruise_weight/(velocity*density*b_red);
y=-0.3*b:9:0.1*b;
z=-0.3*b:9:0.1*b;
[y,z]=meshgrid(y,z);
x=2*b +zeros(10,10);
rc=5;

% %%upwash_avg
syms s
chord_length=((2*S)/(b*(1+TR))*(1-(1-TR)*(2*s)/b));
right_wing=(Circulation/(4*3.14))*((y+s)./( (y+s).^2+ z.^2 + rc.^2)).*(1+(x./sqrt(x.^2+(y+s).^2+z.^2)))*chord_length;
left_wing=(Circulation/(4*3.14))*((y+b+s)./( (y+b+s).^2+ z.^2 + rc.^2)).*(1+(x./sqrt(x.^2+(y+b+s).^2+z.^2)));
I = (1/b)*((left_wing+right_wing)*chord_length);
qwe = vpaintegral(I, s, 0, b);

whos

  Name                Size            Bytes  Class     Attributes

  AR                  1x1                 8  double              
  CR                  1x1                 8  double              
  CT                  1x1                 8  double              
  Circulation         1x1                 8  double              
  I                  10x10                8  sym                 
  S                   1x1                 8  double              
  TR                  1x1                 8  double              
  W                   1x1                 8  double              
  b                   1x1                 8  double              
  b_red               1x1                 8  double              
  chord_length        1x1                 8  sym                 
  cruise_weight       1x1                 8  double              
  density             1x1                 8  double              
  l                   1x1                 8  double              
  lamda               1x1                 8  double              
  left_wing          10x10                8  sym                 
  mach                1x1                 8  double              
  qwe                10x10                8  sym                 
  rc                  1x1                 8  double              
  right_wing         10x10                8  sym                 
  s                   1x1                 8  sym                 
  sound_speed         1x1                 8  double              
  velocity            1x1                 8  double              
  x                  10x10              800  double              
  y                  10x10              800  double              
  z                  10x10              800  double              

surf( y/b, z/b, double(qwe))