post-processing in VIV
Table of Contents
1 delete duplicate rows in fluent output file
data: time history of force, displacement package: excel
steps:
- selete all, select tab
- Data/revove duplicates
3.select default columns, and press ok
https://www.howtogeek.com/198052/how-to-remove-duplicate-rows-in-excel/
2 image and video
2.1 crop images
start point: 5D, 4D upstream
mogrify -crop 388x148+380+622 *.jpg
mogrify -crop 388x168+380+622 *.jpg
2.2 image2video
clc
clear
step=63;
for i=3:step
h=figure(1); % ÏÂÃæÒ»ÐÐÌ滻ΪÏëÒªÏÔÊŸµÄÄÚÈÝ
% set(0,'defaultfigurecolor','w')
f_name=strcat('AnimationFrame',num2str(i,'%.6d'),'.jpg')
aa=imread([f_name]);
cc=imcrop(aa,[20 20 2000 800]);
imshow(cc)
% imshow([f_name]);
% imshow([num2str(i),'.jpg']);
frame = getframe(h);
im = frame2im(frame);
[imind,cm] = rgb2ind(im,256);
% Write to the GIF File?
if i==1
imwrite(imind,cm,['Frame','.gif'],'gif', 'Loopcount',inf,'DelayTime',0.1);
elseif i==step
imwrite(imind,cm,['Frame','.gif'],'gif','WriteMode','append','DelayTime',0.1);
else
imwrite(imind,cm,['Frame','.gif'],'gif','WriteMode','append','DelayTime',0.1);
end
end
2.3 combine videos
3 vorticity contour
3.1 Goal:
get vorticity contour at every time step
3.2 Steps
- load one case and data file
- display vorticity contour with code
a) Select "command editor" and paste the following code
b) change expression if needed
# Session file started: 2019/11/12 15:12:02
# CFX-15.0 build 2013.10.10-08.49-130242
# To avoid unnecessary file pre-processing and modifications, include
# COMMAND FILE at the top of your session file.
# If it is not included, the file is assumed to be older and will be
# modified for backward compatibility.
COMMAND FILE:
CFX Post Version = 15.0
END
VIEW:View 1
Camera Mode = User Specified
CAMERA:
Option = Pivot Point and Quaternion
Pivot Point = 2, 0.6, 0.3
Scale = 0.749315
Pan = 0, 0
Rotation Quaternion = 0, 0, 0, 1
END
END
> update
LIBRARY:
CEL:
EXPRESSIONS:
revortex = Velocity.Curl Z*0.1/1.1686
END
END
END
EXPRESSION EVALUATOR:
Evaluated Expression = revortex
END
> forceupdate EXPRESSION EVALUATOR
USER SCALAR VARIABLE:divortex
Boundary Values = Conservative
Calculate Global Range = Off
Expression = revortex
Recipe = Expression
Variable to Copy = Pressure
Variable to Gradient = Pressure
END
PLANE:Plane 1
Apply Instancing Transform = On
Apply Texture = Off
Blend Texture = On
Bound Radius = 0.5 [m]
Colour = 0.75, 0.75, 0.75
Colour Map = Default Colour Map
Colour Mode = Constant
Colour Scale = Linear
Colour Variable = Pressure
Colour Variable Boundary Values = Conservative
Culling Mode = No Culling
Direction 1 Bound = 1.0 [m]
Direction 1 Orientation = 0 [degree]
Direction 1 Points = 10
Direction 2 Bound = 1.0 [m]
Direction 2 Points = 10
Domain List = /DOMAIN GROUP:All Domains
Draw Faces = On
Draw Lines = Off
Instancing Transform = /DEFAULT INSTANCE TRANSFORM:Default Transform
Invert Plane Bound = Off
Lighting = On
Line Colour = 0, 0, 0
Line Colour Mode = Default
Line Width = 1
Max = 0.0 [Pa]
Min = 0.0 [Pa]
Normal = 1 , 0 , 0
Option = XY Plane
Plane Bound = None
Plane Type = Slice
Point = 0 [m], 0 [m], 0 [m]
Point 1 = 0 [m], 0 [m], 0 [m]
Point 2 = 1 [m], 0 [m], 0 [m]
Point 3 = 0 [m], 1 [m], 0 [m]
Range = Global
Render Edge Angle = 0 [degree]
Specular Lighting = On
Surface Drawing = Smooth Shading
Texture Angle = 0
Texture Direction = 0 , 1 , 0
Texture File =
Texture Material = Metal
Texture Position = 0 , 0
Texture Scale = 1
Texture Type = Predefined
Tile Texture = Off
Transform Texture = Off
Transparency = 0.0
X = 0.0 [m]
Y = 0.0 [m]
Z = 0.3 [m]
OBJECT VIEW TRANSFORM:
Apply Reflection = Off
Apply Rotation = Off
Apply Scale = Off
Apply Translation = Off
Principal Axis = Z
Reflection Plane Option = XY Plane
Rotation Angle = 0.0 [degree]
Rotation Axis From = 0 [m], 0 [m], 0 [m]
Rotation Axis To = 0 [m], 0 [m], 0 [m]
Rotation Axis Type = Principal Axis
Scale Vector = 1 , 1 , 1
Translation Vector = 0 [m], 0 [m], 0 [m]
X = 0.0 [m]
Y = 0.0 [m]
Z = 0.0 [m]
END
END
# Sending visibility action from ViewUtilities
>show /PLANE:Plane 1, view=/VIEW:View 1
CONTOUR:Contour 1
Apply Instancing Transform = On
Clip Contour = Off
Colour Map = Default Colour Map
Colour Scale = Linear
Colour Variable = divortex
Colour Variable Boundary Values = Conservative
Constant Contour Colour = Off
Contour Range = User Specified
Culling Mode = No Culling
Domain List = /DOMAIN GROUP:All Domains
Draw Contours = On
Font = Sans Serif
Fringe Fill = On
Instancing Transform = /DEFAULT INSTANCE TRANSFORM:Default Transform
Lighting = On
Line Colour = 0, 0, 0
Line Colour Mode = Default
Line Width = 1
Location List = /PLANE:Plane 1
Max = 2 [s^-1]
Min = -2 [s^-1]
Number of Contours = 100
Show Numbers = Off
Specular Lighting = On
Surface Drawing = Smooth Shading
Text Colour = 0, 0, 0
Text Colour Mode = Default
Text Height = 0.024
Transparency = 0.0
Value List = 0 [s^-1],1 [s^-1]
OBJECT VIEW TRANSFORM:
Apply Reflection = Off
Apply Rotation = Off
Apply Scale = Off
Apply Translation = Off
Principal Axis = Z
Reflection Plane Option = XY Plane
Rotation Angle = 0.0 [degree]
Rotation Axis From = 0 [m], 0 [m], 0 [m]
Rotation Axis To = 0 [m], 0 [m], 0 [m]
Rotation Axis Type = Principal Axis
Scale Vector = 1 , 1 , 1
Translation Vector = 0 [m], 0 [m], 0 [m]
X = 0.0 [m]
Y = 0.0 [m]
Z = 0.0 [m]
END
END
# Sending visibility action from ViewUtilities
>show /CONTOUR:Contour 1, view=/VIEW:View 1
# Sending visibility action from ViewUtilities
>hide /DEFAULT LEGEND:Default Legend View 1, view=/VIEW:View 1
# Session file stopped: 2019/11/12 15:16:00
- add time value
- animation
timestep selector >> animation>> animation options
4 time histories of displacement, lift and drag
FFT– find the frequency
package: matlab
%% inputs: time, displacement, lift and drag coefficents
% author: guofei, kaiming ai
% output: normalised displacement vs time
clear;
clc;
%% read data
data=xlsread('gap0.005ur7.xlsx');
A1=data(800:4233,1); % time on one cycle
A2=data(800:4233,2); % displacement
A3=data(800:4233,3); % lift
A4=data(800:4233,4); % drag
% plot(A1,A2)
%% plot data
figure(1);
U=1.1686; %free stream velocity
fig_hei=0.28;
fig_wei=0.9;
lef_cor_x=0.08;
lef_cor_y=0.1;
% sub-figure1: drag history
subplot(3,1,1,'position', [lef_cor_x lef_cor_y+fig_hei+fig_hei fig_wei fig_hei])
plot(A1*U/0.1,A4,'b-');
ylabel('\itC_{D}','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([20,400,-inf,inf])
set(gca,'xticklabel',[])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
%sub-figure2: Cl, lift coefficient history
subplot(3,1,2,'position', [lef_cor_x lef_cor_y+fig_hei fig_wei fig_hei])
plot(A1*U/0.1,A3,'r-');
ylabel('\itC_{l}','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([20,400,-inf,inf])
set(gca,'xticklabel',[])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
%subplot 3: A/D, normalised displacement history
subplot(3,1,3,'position', [lef_cor_x lef_cor_y fig_wei fig_hei])
plot(A1*U/0.1,A2/0.1,'r-');
ylabel('\itA/D','fontsize',20,'fontname','Times New Roman');
xlabel('\ittU/D','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([20,400,-inf,inf])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% FFT
Data_FFT=[A2,A3,A4];
S=[Data_FFT(:,1)-mean(Data_FFT(:,1)),Data_FFT(:,2)-mean(Data_FFT(:,2)),Data_FFT(:,3)-mean(Data_FFT(:,3))];
Fs=200;% sample freq
N=9000;% number of sample
t=[0:1/Fs:N/Fs];
Y=fft(S,N);
Ayy=(abs(Y));
%Ayy=Ayy/(N/2);
Ayy_1=Ayy(:,1);
Ayy_2=Ayy(:,2);
Ayy_3=Ayy(:,3);
F=([1:N]-1)*Fs/N;
%%%%%%%%%%
% plot 2
%%%%%%%%%%%%%
figure(2);
%FFT of cd
subplot(3,1,1,'position', [lef_cor_x lef_cor_y+fig_hei+fig_hei fig_wei fig_hei])
plot(F(1:N/2),Ayy_3(1:N/2),'b-','linewidth',2);
ylabel('\itAmplitude','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([0,10,0,inf])
set(gca,'xticklabel',[])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
%FFT of cl
subplot(3,1,2,'position', [lef_cor_x lef_cor_y+fig_hei fig_wei fig_hei])
plot(F(1:N/2),Ayy_2(1:N/2),'b-','linewidth',2);
ylabel('\itAmplitude','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([0,10,0,3e3])
set(gca,'xticklabel',[])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
% subplot 3 : dis
subplot(3,1,3,'position', [lef_cor_x lef_cor_y fig_wei fig_hei])
plot(F(1:N/2),Ayy_1(1:N/2),'b-','linewidth',2);
xlabel('\itf','fontsize',20,'fontname','Times New Roman');
ylabel('\itAmplitude','fontsize',20,'fontname','Times New Roman');
set(gca,'fontsize',20,'fontname','Times New Roman')
axis([0,10,0,100])
box off
ax2 = axes('Position',get(gca,'Position'),...
'XAxisLocation','top',...
'YAxisLocation','right',...
'Color','none',...
'XColor','k','YColor','k');
set(ax2,'YTick', []);
set(ax2,'XTick', []);
box on
%% mean value of Cd
mean_Cd = mean(A4)
%% rms_Cd
rms_Cd = rms(A4)
%% rms_cl
rms_Cl = rms(A3)
%% displacement
A2_mean = A2(A2>0.06);
s = sum(A2_mean);
l = length(find(A2>0.06));
dis_ave = s/l;
%% RMS of displacement, max displacement
Rms = rms(A2);
dis = Rms*(2)^0.5
max_dis = max (A2)
K = F';
C = data(:,1)*U/0.1;