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function trm=radial(ffreqs,dirs,wns,z,depth,xpos,ypos); |
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%This transfer function takes the along beam radial velocities from an ADCP |
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%and transfers them to surface displacement for use in DIWASP. |
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%This was added to DIWASP on 6/22/07 |
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% Modified from Hoshimoto (1997) |
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transH=.4; % transducer face height off the bottom |
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dist=(xpos^2+ypos^2)^.5; %horizontal distance from origin |
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a=atan(dist/(z-transH));%beam angle from the vertical |
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% compute the axis angle |
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if xpos > 0 & ypos > 0 % 1st quadrant |
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B= acos(xpos/dist); |
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elseif xpos < 0 & ypos < 0 % 3 quadrant |
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B= pi + acos(abs(xpos/dist)); |
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elseif xpos < 0 & ypos > 0 % 2nd quadrant |
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B= pi/2 + asin(abs(xpos/dist)); |
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elseif xpos > 0 & ypos < 0 % 4th quadrant |
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B = 3*pi/2 + asin(abs(xpos/dist)); |
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end |
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%note: Dirs and B are both measured from the x-axis with positive angles |
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%being counterclockwise |
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A1=(ones(1,length(dirs))*cos(a));%a vector of length dirs of the cos(a) |
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FL=ffreqs*ones(1,length(dirs));%Create a vector of length ffreqs/length dirs so that we can multiply |
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%through in the trm function |
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KZ=cosh(wns*z)./sinh(wns*depth); |
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%include a maximum cuttoff for the velocity response function |
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KZ(find(KZ<0.1))=0.1; |
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KZ(find(isnan(KZ)))=1; |
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KZi=sinh(wns*z)./sinh(wns*depth); |
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%include a maximum cuttoff for the velocity response function |
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KZi(find(KZi<0.1))=0.1; |
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KZi(find(isnan(KZi)))=1; |
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trm=FL.*(KZ*(sin(a)*cos(dirs-B))-(i*KZi)*A1); |
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