# how to pull correct h into h(i)

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John Daniels on 24 Apr 2022
Commented: John Daniels on 24 Apr 2022
M=1.4; %mach speed
l=1.68; %length , m
t=0.15 ; %thickness, m
dx=0.168; %delta x, m
dy=0.015; %delta y, m
dz=0.68668; %delta z, m
Ta=216.66; %free stream temperature, K
K=1.401; %specific heat ratio
pr=0.72178; %prandtl number
r=(pr)^(1/3); %recovery factor
Tstag=Ta*(1+((K-1)/2)*((M*(cosd(20)))^(2))); %stagnation temperature
Ka=121.0 % Aluminum,Thermal Conductivity, W/m-k
Kt=6.7 %Titanium, Thermal Conductivity, W/m-k
Kc=30.758 %Carbon-carbon,Thermal Conductivity, W/m-k
%matrix 1x4 of each node
N_1=[ 0 21 0 0];
N_2=[ 0 30 21 0];
N_3=[ 0 44 30 0];
N_4=[ 0 54 44 0];
N_5=[ 0 60 54 0];
N_6=[ 0 0 60 0 ];
N_7=[ 0 0 56 60];
N_8=[0 0 48 56 ];
N_9=[0 0 36 48];
N_10=[0 0 29 36];
N_11=[0 0 0 29];
N_12=[21 37 0 0];
N_13=[ 37 49 0 0];
N_14=[49 57 0 0];
N_15=[ 57 61 0 0];
N_16=[61 0 0 0 ];
N_17=[59 0 0 61];
N_18=[53 0 0 59];
N_19=[ 43 0 0 53];
N_20=[29 0 0 43];
N_21=[2 22 12 1];
N_22=[ 30 23 37 21];
N_23=[ 31 24 38 22];
N_24=[32 25 39 23];
N_25=[33 26 40 24];
N_26=[34 27 41 25];
N_27=[35 28 42 26];
N_28=[36 29 43 27];
N_29=[ 10 11 20 28];
N_30=[ 3 31 22 2];
N_31=[44 32 23 30];
N_32=[ 45 33 24 31];
N_33=[ 46 34 25 32];
N_34=[ 47 35 26 33];
N_35=[ 48 36 27 34];
N_36=[ 9 10 28 35];
N_37=[ 22 38 13 12];
N_38=[ 23 39 49 37];
N_39=[ 24 40 50 30];
N_40=[ 25 41 51 39];
N_41=[26 42 52 40];
N_42=[27 43 53 41];
N_43=[28 20 19 42];
N_44=[ 4 45 31 3];
N_45=[54 46 32 44];
N_46=[ 55 47 33 45];
N_47=[ 56 48 34 46];
N_48=[ 8 9 35 47];
N_49=[ 38 50 14 13];
N_50=[ 39 51 57 49];
N_51=[ 40 52 58 50];
N_52=[ 41 53 59 51];
N_53=[ 42 19 18 52];
N_54=[ 5 55 45 4 ];
N_55=[ 60 7 55 5 ];
N_56=[ 7 8 47 55];
N_57=[ 50 58 15 14];
N_58=[51 59 61 57];
N_59=[ 52 18 17 58];
N_60=[ 6 7 55 5];
N_61=[58 17 16 15];
% 61x4 matrix
C=[N_1;N_2;N_3;N_4;N_5;N_6;N_7;N_8;N_9;N_10;N_11;N_12;N_13;N_14;...
N_15;N_16;N_17;N_18;N_19;N_20;N_21;N_22;N_23;N_24;N_25;N_26;N_27;N_28;N_29;...
N_30;N_31;N_32;N_33;N_34;N_35;N_36;N_37;N_38;N_39;N_40;N_41;N_42;N_43;...
N_44;N_45;N_46;N_47;N_48;N_49;N_50;N_51;N_52;N_53;N_54;N_55;N_56;N_57;N_58;...
N_59;N_60;N_61]
k=0.168:0.168:1.68;
for x=1:length(k)
if k(x)>=0.03 && k(x)<=0.06
h(x)=1.437*k(x)^(-0.279)
elseif k(x)>=0.07 && k(x)<=0.83
h(x)=5.313*k(x)^(-0.121)
else k(x)>=0.85 && k(x)<=1.68
h(x)=(-2.0945)*k(x)+7.0609
end
end
h
% for i=2:1:5
alr=Ka*(dy/dx)
alb=Ka*(dx/dy)
A=zeros(61,61);
for i=2:1:5
A(i,i)=((h(i))*(dz)*Ta)/(alb+alr)
A(i,C(i,2))=alr
A(i,C(i,3))=alb
end
for i=6
A(i,i)=2*(h(i)*dz/2)+alb
A(i,C(i,3))=alb
end
for i=7:1:10
A(i,i)=(h(i)*(dz)*Ta)/(alb+alr)
A(i,C(i,3))=alr
A(i,C(i,4))=alb
end
for i=11
A(i,i)=2*(h(i)*dz/2)+alr
A(i,C(i,4))=alr
end
for i=12:1:15
A(i,i)=(h(i)*(dz)*Ta)/(alb+alr)
A(i,C(i,1))=alr
A(i,C(i,2))=alb
end
for i=16
A(i,i)=2*(h(i)*dz/2)+alb
A(i,C(i,1))=alb
end
for i=17:1:20
A(i,i)=(h(i)*(dz)*Ta)/(alb+alr)
A(i,C(i,1))=alr
A(i,C(i,4))=alb
end
I need to put h value that is correctly coorsponse to correct Node, like I want A(2,2)to have h=6.5959, A(3,3)=6.0625,
John Daniels on 24 Apr 2022
A(2,2)=A(12,12)
A(3,3)=A(13,13)
A(4,4)=A(14,14)
and so on..

Sulaymon Eshkabilov on 24 Apr 2022
Hi,
You meant A(2,2) to have h=6.5929, A(3,3) to have h = 6.0625, correct?
for i=2:1:5
A(i,i)=((h(i-1))*(dz)*Ta)/(alb+alr)
A(i,C(i,2))=alr
A(i,C(i,3))=alb
end
Your code does not run beyond h(10). Because the length of k is 10 and the number of compted values of h is also 10.
Moreover, [for .. end] loops for a single value of h are not needed, e.g.:
for i=6
A(i,i)=2*(h(i)*dz/2)+alb
A(i,C(i,3))=alb
end
can be computed with:
A(6,6)=2*(h(6)*dz/2)+alb;
A(6,C(6,3))=alb;
John Daniels on 24 Apr 2022
thank you!!