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Ripples
on 4 Nov 2024
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Cite your audio source here (if applicable):
drawframe(1);drawframe(70);
Write your drawframe function below
function drawframe(f)
persistent M W
if f==1
% Capillary wave parameters
s=.072; % water surface tension (N/m)
% r=1025; % saltwater density (kg/m^3)
r=1e3; % freshwater density (kg/m^3)
a=.03; % ripple amplitude (m)
T=1; % ripple period (s)
w=2*pi/T; % angular frequency (rad/s)
% Dispersion
k=(w^2*r/s)^(1/3); % wavenumber (rad/m)
L=2*pi/k; % wavelength (m)
c=L/T; % wave celerity (m/s)
ph=pi/2; % initial phase (rad)
Fs=24; % Sampling frequency (96/4)
t=1/Fs:1/Fs:4; % Time vector
% Spatial domain
x=-1:0.005:1;
y=-1:0.005:1;
% Water surface elevation calculation
M=C(t,x,y,a,w,k,c,ph);
% Water surface
W=surf(x,y,squeeze(M(1,:,:)),'EdgeColor','none','FaceColor','b','FaceAlpha',1,'FaceLighting','gouraud');
set(gca,'Position',[0 0 1 1])
axis off
axis([-.8 .8 -.8 .8 [-2 50]*max(M,[],'all')])
view(2)
light(St='l',Po=[2 2 100*max(M,[],'all')],Col='c')
lighting g
material shiny
else
% Updating the water surface
W.ZData=squeeze(M(f,:,:));
end
end
function M=C(t,x,y,a,w,k,c,ph)
% Capillary wave calculation function
rng(0)
n=40; % Total number of ripples within the time duration
xc=-0.8+1.6*rand(1,n); yc=-0.8+1.6*rand(1,n); % Some random coordinates for each ripple
r=max(0.5,rand(1,length(xc))); % Some amplitude variance for each ripple
[X,Y]=meshgrid(x,y);
M=zeros(length(t),length(x),length(y),length(xc));
for j=1:numel(xc)
for i=1:numel(t)
tf=floor(length(t)/length(xc));
tt=t(max(i-(j-1)*tf,1));
if i>(j-1)*tf+1
M(i,:,:,j)=a/length(xc)*(t(end-(j-1)*tf)-tt)/t(end-(j-1)*tf)*r(j)*sin(w*tt-k*sqrt((X-xc(j)).^2+(Y-yc(j)).^2)+ph);
end
x1=abs(x-xc(j))<c*tt*3;
y1=abs(y-yc(j))<c*tt*3;
% Mask
m=x1.*y1';
% 3D Hanning window mask to simulate ripple propagation & damping in space
m(m==1)=ones(numel(find(x1==1)),numel(find(y1==1)))'.*(hann(numel(find(x1==1))).*hann(numel(find(y1==1)))')';
M(i,:,:,j)=squeeze(M(i,:,:,j))'.*m';
end
end
M=sum(M,4);
end
