- Author:
- aram148 <a.rampadarath@auckland.ac.nz>
- Date:
- 2021-11-04 16:02:42+13:00
- Desc:
- Updated USMC-Bursztyn model
- Permanent Source URI:
- http://models.cellml.org/workspace/6b0/rawfile/4c1ab73f48d7150c2094cf8017425482a1594ccf/USMC/Maggio2012/airwayradius.m
function drdt=airwayradius(t,r,P0,kappa)
%% Parameter values used for both ASM-aw and Anafi-Wilson coupled system
Ri_sq=0.0174;
rmax_sq=0.1980;
N1=1;
N2=8;
P1=0.4021;
P2=-33.3394;
rmax=0.4450;
rho=1;
E=254.9;%cmH2O/ml %Elastance of acinus
L = 2.6852;%mm %airway length
% L=2*pi*rmax;
aa = 10.19716213; % Conversion factor for kg*(mm)^(-1)*(s)^(-2) to cmH20
moo = 1.9008e-8; % dynamic viscosity kg(mm)^(-1)s^(-1)
f=0.25;
% %% Anafi-Wilson type pressure difference
% P01=P011;
%
% Pawbb = Pawb*abs(sin(2*pi*f));
%
% Raw = 8*aa*L*moo/(pi*r.^4);
%
% Paw = P01 + Pawbb;%pressure in airway
%
% Pab = Pawb*E/(E.^2 + (2*pi*f*Raw).^2)^0.5;
%
% alph = atan(2*pi*f*Raw/E);
%
% Pabb = Pab*abs(sin(2*pi*f*t-alph));%.*(t<a)+((10*Pab))*abs(sin(2*pi*f*t-alph)).*(t>=a).* (t<=b)...
%
% Pa = P01 + Pabb; %pressure in acinus
% vv = 0.2 +0.04*Pa; %Acinus volume
% xx = 1-(r(8)/vv.^(1/3));
% P_lumen = (Paw + Pa)/2;
% %P0=P_lumen + Pa;
% tau = Pa + Pa*(1.4*xx+2.1*xx.^2);%parenchymal tethering force
%Transmural pressure as a function of force.
% Ptm=Pmin-((force*r_ref)./r(8))+tau;
Ptm=((P0)-(kappa./r));
if Ptm<=0
% a=a0(s).*(1-(Ptm./P1)).^(-N1(s));
rad=sqrt(Ri_sq*(1-(Ptm/P1)).^-N1);
elseif Ptm>=0
% a=(1-((1-a0(s)).*(1-(Ptm./P2)).^(-N2(s))));
rad=sqrt(rmax_sq-(rmax_sq-Ri_sq)*(1-(Ptm/P2)).^-N2);
end
drdt=rho*(rad-(r)); % this is to be used for the orginal DM coupled system.
