Issue 1:
When you defined the function as
[disp_dot]=stage2(x,t)
There is not role of t function input data t in the function.
Issue 2:
In the following one parenthesis bracket required at last.
disp_dot(2)=(1/m)*((KB*AB/(0.000058402+((ASBD+AB)*x(1))^1.4)-(PT*AT)-(m*g)+(PSB*ASB)-(PST*AST)));
Now I have defined the function as
function [disp_dot]=stage2(x)%Stage_2 calculation for displacement and pressure
m=23.5; %Stage_2:From bottom choked till bottom is exhausted; top is exhausted
ODB=0.122;
IDB=0.04625;
g=9.8;
ODT=0.104;
IDT=0.042;
Patm=100000;
dt=0.0001; %time increment value
L=0.11; %This is the length where adiabatic condition starts in top chamber; the length of the leg of the air distributor
AT=pi*(ODT^2-IDT^2)/4;
AB=pi*(ODB^2-IDB^2)/4;
PT=Patm;
ODSBD=0.1285;
IDSBD=0.122;
ASBD=pi*(ODSBD^2-IDSBD^2)/4;
ASB=0.00451183;
AST=0.001267892;
CFM=840; %air inflow
CFMm=CFM*(1/2118.88);
v=CFMm/AB;
v=5;
PST=Patm;
PSB=Patm;
PT=Patm;
LB=0.0259; %This is the length where bottom chamber becomes adiabatic during upward displacement of the piston
PBinitial=((PT*AT)+(m*g)+(PST*AST)-(PSB*ASB))/AB;
KB=PBinitial*(AB*LB)^1.4;
disp_dot(1)=x(2);
disp_dot(2)=(1/m)*((KB*AB/(0.000058402+((ASBD+AB)*x(1))^1.4)-(PT*AT)-(m*g)+(PSB*ASB)-(PST*AST))); %Constant value is from bottom channel 4 in excel
end
When I ran the code here is the output
>> y1=[1,2]
y1 =
1 2
>> y=stage2(y1)
y =
2.0000 -26.1197
Please note in the fuction code x define as 2 length vector, which require x(1) and x(2), that why I have passed the y=[valuue1 value 2] to function
Hope it helps!
