initial commit / add all books

28 files changed, 256 insertions, 0 deletions

diff --git a/548/CH4/EX4.01/4_01.sce b/548/CH4/EX4.01/4_01.sce
new file mode 100755
index 000000000..a29414dbc
--- /dev/null
+++ b/548/CH4/EX4.01/4_01.sce
@@ -0,0 +1,6 @@
+pathname=get_absolute_file_path('4_01.sce')

+filename=pathname+filesep()+'4_01data.sci'

+exec(filename)

+printf("\Answer:\n")

+printf("\n\area of the duct exit: %f m^2\n\n",A2)

+

diff --git a/548/CH4/EX4.02/4_02.sce b/548/CH4/EX4.02/4_02.sce
new file mode 100755
index 000000000..6f6c5b37f
--- /dev/null
+++ b/548/CH4/EX4.02/4_02.sce
@@ -0,0 +1,6 @@
+pathname=get_absolute_file_path('4_02.sce')

+filename=pathname+filesep()+'4_02data.sci'

+exec(filename)

+printf("\Answer:\n")

+printf("\n\density of air at the duct exit: %f Kg/m^3\n\n",D2)

+

diff --git a/548/CH4/EX4.03/4_03.sce b/548/CH4/EX4.03/4_03.sce
new file mode 100755
index 000000000..e971c68a1
--- /dev/null
+++ b/548/CH4/EX4.03/4_03.sce
@@ -0,0 +1,8 @@
+pathname=get_absolute_file_path('4_03.sce')

+filename=pathname+filesep()+'4_03data.sci'

+exec(filename)

+disp("P1+(D*V1^2/2)=Pa+(D*Va^2/2)","Bernoulli equation");

+Va=[(2*(P1-Pa)/D)+(V1)^2]^0.5;disp(Va,"Va=")

+printf("\Answer:\n")

+printf("\n\velocity at a point A on airfoil: %f m/s\n\n",Va)

+

diff --git a/548/CH4/EX4.04/4_04.sce b/548/CH4/EX4.04/4_04.sce
new file mode 100755
index 000000000..acbbf27c5
--- /dev/null
+++ b/548/CH4/EX4.04/4_04.sce
@@ -0,0 +1,6 @@
+pathname=get_absolute_file_path('4_04.sce')

+filename=pathname+filesep()+'4_04data.sci'

+exec(filename)

+printf("\Answer:\n")

+printf("\n\pressure at the duct exit: %f N/m^2\n\n",P2)

+

diff --git a/548/CH4/EX4.05/4_05.sce b/548/CH4/EX4.05/4_05.sce
new file mode 100755
index 000000000..ad997bcba
--- /dev/null
+++ b/548/CH4/EX4.05/4_05.sce
@@ -0,0 +1,6 @@
+pathname=get_absolute_file_path('4_05.sce')

+filename=pathname+filesep()+'4_05data.sci'

+exec(filename)

+D=1.067*D*V^2*R;

+printf("\Answer:\n")

+printf("\n\Aerodynamic force exerted by surface pressure distribution: %f N\n\n",D)

diff --git a/548/CH4/EX4.06/4_06.sce b/548/CH4/EX4.06/4_06.sce
new file mode 100755
index 000000000..6d9163d6e
--- /dev/null
+++ b/548/CH4/EX4.06/4_06.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_06.sce')

+filename=pathname+filesep()+'4_06data.sci'

+exec(filename)

+printf("\Answer:\n")

+printf("\n\internal energy per unit mass in SI unit: %f J/Kg.K\n\n",e)

+printf("\n\internal energy per unit mass in English enginering unit: %f Ft.Lb/slug\n\n",e1)

+printf("\n\enthalpy per unit mass in SI unit: %f J/Kg.K\n\n",h)

+printf("\n\enthalpy per unit mass in English enginering unit: %f Ft.Lb/slug\n\n",h1)

+

+

diff --git a/548/CH4/EX4.07/4_07.sce b/548/CH4/EX4.07/4_07.sce
new file mode 100755
index 000000000..1ef37203f
--- /dev/null
+++ b/548/CH4/EX4.07/4_07.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_07.sce')

+filename=pathname+filesep()+'4_07data.sci'

+exec(filename)

+disp("P2/P1=(T2/T1)^y/y-1","For isentropic flow","let P2 be the pressure at that point of wing");

+P2=P1*(T/T1)^(y/(y-1));disp(P2,"P2=")

+printf("\Answer:\n")

+printf("\n\Pressure at this point: %f N/m^2\n\n",P2)

diff --git a/548/CH4/EX4.08/4_08.sce b/548/CH4/EX4.08/4_08.sce
new file mode 100755
index 000000000..3330b335e
--- /dev/null
+++ b/548/CH4/EX4.08/4_08.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_08.sce')

+filename=pathname+filesep()+'4_08data.sci'

+exec(filename)

+disp("T2=T1*(P2/P1)^((y-1)/y)","from isentropic condition:")

+T2=T1*(P2/P1)^((y-1)/y)//temperature at exit

+printf("\Answer:\n")

+printf("\n\Gas temperature at the exit: %f K\n\n",T2)

diff --git a/548/CH4/EX4.09/4_09.sce b/548/CH4/EX4.09/4_09.sce
new file mode 100755
index 000000000..908c40108
--- /dev/null
+++ b/548/CH4/EX4.09/4_09.sce
@@ -0,0 +1,18 @@
+pathname=get_absolute_file_path('4_09.sce')

+filename=pathname+filesep()+'4_09data.sci'

+exec(filename)

+disp("So V1^2=2Cp*(To-T1)","CpTo=CpT1+(V1^2)/2","From energy equation:","let V1 be the velocity of throat")

+V1=(2*Cp*(To-T1))^0.5;

+printf("\n\Velocity at throat: %f m/s\n\n",V1)

+disp("So Ve^2=2Cp*(To-Te)","CpTo=CpTe+(Ve^2)/2","From energy equation:","let Ve be the velocity of exit")

+Ve=(2*Cp*(To-Te))^0.5;

+printf("\n\Velocity at the exit: %f m/s\n\n",Ve)

+disp("A1=Mt/(D1*V1)","Area of throat")

+A1=Mt/(D1*V1);

+printf("\n\Area of throat: %f m^2\n\n",A1)

+disp("Ae=Mt/(De*Ve)","Area of the exit")

+Ae=Mt/(De*Ve);

+printf("\n\Area of the exit: %f m^2\n\n",Ae)

+

+

+

diff --git a/548/CH4/EX4.10/4_10.sce b/548/CH4/EX4.10/4_10.sce
new file mode 100755
index 000000000..db4b2b2f4
--- /dev/null
+++ b/548/CH4/EX4.10/4_10.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_10.sce')

+filename=pathname+filesep()+'4_10data.sci'

+exec(filename)

+disp("So Va^2=2Cp*(T-Ta)+V^2","CpT+(V^2)/2=CpTa+(Va^2)/2","From energy equation:","let Va be the velocity of the point A")

+Va=(2*Cp*(T-Ta)+V^2)^0.5;disp(Va,"Va=")

+printf("\Answer:\n")

+printf("\n\Velocity at point A: %f m/s\n\n",Va)

diff --git a/548/CH4/EX4.11/4_11.sce b/548/CH4/EX4.11/4_11.sce
new file mode 100755
index 000000000..1606f6d64
--- /dev/null
+++ b/548/CH4/EX4.11/4_11.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_11.sce')

+filename=pathname+filesep()+'4_11data.sci'

+exec(filename)

+disp("Mach No M=V/a");

+M=V/a;disp(M,"M=")

+printf("\Answer:\n")

+printf("\n\Mach No of the jet transport: %f\n\n",M)
\ No newline at end of file
diff --git a/548/CH4/EX4.12/4_12.sce b/548/CH4/EX4.12/4_12.sce
new file mode 100755
index 000000000..80fe1ff55
--- /dev/null
+++ b/548/CH4/EX4.12/4_12.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_12.sce')

+filename=pathname+filesep()+'4_12data.sci'

+exec(filename)

+disp("Mach No at Throat Mt=V1/a");

+Mt=V1/a;disp(Mt,"Mt=")

+disp("Mach No at Throat Me=Ve/Ae");

+Me=Ve/Ae;disp(Me,"Me=")

+printf("\Answer:\n")

+printf("\n\Mach No at throat: %f\n\n",Mt)

+printf("\n\Mach No at exit: %f\n\n",Me)
\ No newline at end of file
diff --git a/548/CH4/EX4.13/4_13.sce b/548/CH4/EX4.13/4_13.sce
new file mode 100755
index 000000000..4730c0e1d
--- /dev/null
+++ b/548/CH4/EX4.13/4_13.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_13.sce')

+filename=pathname+filesep()+'4_13data.sci'

+exec(filename)

+disp("(2(P1-P2)/(D1(1-(A2/A1)^2)))^0.5=(2*(Dp)/(D1*(1-r^2)))^0.5","Airflow velocity at test section V=");

+V=(2*(Dp)/(D1*(1-r^2)))^0.5;disp(V,"V=");

+printf("\Answer:\n")

+printf("\n\Airflow velocity in the test section: %f m/s\n\n",V)

diff --git a/548/CH4/EX4.14/4_14.sce b/548/CH4/EX4.14/4_14.sce
new file mode 100755
index 000000000..48f752179
--- /dev/null
+++ b/548/CH4/EX4.14/4_14.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_14.sce')

+filename=pathname+filesep()+'4_14data.sci'

+exec(filename)

+disp("P2+D(V2^2-V1^2)/2","pressure at reservoir P1=")

+P1=P2+D*(V2^2-V1^2)/2;disp(P1,"P1=")

+disp("Mt=D*A1*V1","mass flow rate :")

+Mt=D*A1*V1;disp(Mt,"Mt=")

+printf("\Answer:\n")

+printf("\n\pressure required to have a velocity of 40 m/s at test section: %f N/m^2\n\n",P1)

+printf("\n\mass flow through the wind tunnel: %f Kg/s\n\n",Mt)

diff --git a/548/CH4/EX4.15/4_15.sce b/548/CH4/EX4.15/4_15.sce
new file mode 100755
index 000000000..60a0071b9
--- /dev/null
+++ b/548/CH4/EX4.15/4_15.sce
@@ -0,0 +1,11 @@
+pathname=get_absolute_file_path('4_15.sce')

+filename=pathname+filesep()+'4_15data.sci'

+exec(filename)

+disp("V2 propertional to (P2-P1)^0.5","velocity in test section is propertional to square root of pressure difference")

+V2=(40)*2^(0.5);disp(V2,"velocity after pressure difference is doubled is squareroot 2 times 40")

+disp("(2(P1-P2)/(D(1-(A2/A1)^2)))^0.5=(2*(Dp)/(D*(1-(1/R)^2)))^0.5","Airflow velocity at test section V3=");

+V3=(2*(Dp)/(D*(1-(1/R)^2)))^0.5;disp(V3,"V3=");

+printf("\Answer:\n")

+printf("\n\Airflow velocity in the test section after doubling pressure difference: %f m/s\n\n",V2)

+printf("\n\Airflow velocity in the test section after doubling contraction ratio: %f m/s\n\n",V3)

+

diff --git a/548/CH4/EX4.16/4_16.sce b/548/CH4/EX4.16/4_16.sce
new file mode 100755
index 000000000..601272339
--- /dev/null
+++ b/548/CH4/EX4.16/4_16.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_16.sce')

+filename=pathname+filesep()+'4_16data.sci'

+exec(filename)

+disp("Vt=(2(Po-P)/D)^0.5","True velocity of airplane")

+Vt=sqrt(2*(Po-P)/D);disp(Vt,"Vt=");

+disp("Ve=(2(Po-P)/Ds)^0.5","Eqivalent airspeed of airplane")

+Ve=sqrt(2*(Po-P)/Ds);disp(Ve,"Ve=");

+printf("\Answer:\n")

+printf("\n\True velocity of the airplane: %f m/s\n\n",Vt)

+printf("\n\Equivalent airspeed of the airplane: %f m/s\n\n",Ve)

diff --git a/548/CH4/EX4.17/4_17.sce b/548/CH4/EX4.17/4_17.sce
new file mode 100755
index 000000000..f20d54ff9
--- /dev/null
+++ b/548/CH4/EX4.17/4_17.sce
@@ -0,0 +1,15 @@
+pathname=get_absolute_file_path('4_17.sce')

+filename=pathname+filesep()+'4_17data.sci'

+exec(filename)

+disp("M1^2=2*[(Po/P1)^((y-1)/y)-1]/(y-1))","let Mach no at which the airplane flying is M1 then")

+M1=sqrt(2*[(Po/P1)^((y-1)/y)-1]/(y-1));disp(M1,"M1=");

+a1=sqrt(y*R*T);disp(a1,"a1=(y*R*T)^0.5","speed of sound at that point");

+V1=sqrt(2*a1^2*[(Po/P1)^((y-1)/y)-1]/(y-1));

+disp(V1,"V1=","V1^2=2*a1^2*[(Po/P1)^((y-1)/y)-1]/(y-1)","equvalent air speed V1")

+R=((y-1)/y);

+Vc=sqrt([2*a^2*[(((Po-P1)/P)+1)^((y-1)/y)-1]/(y-1)]);

+disp(Vc,"Vc=","Vc^2=2*a^2*[((Po-P1)/P)+1)^((y-1)/y)-1]/(y-1)","caliberated air speed Vc")

+printf("\Answer:\n")

+printf("\n\mach no at which airplane is flying: %f \n\n",M1)

+printf("\n\True airspeed of the airplane: %f m/s\n\n",V1)

+printf("\n\caliberated airspeed of the airplane: %f m/s\n\n",Vc)

diff --git a/548/CH4/EX4.18/4_18.sce b/548/CH4/EX4.18/4_18.sce
new file mode 100755
index 000000000..8edfc1096
--- /dev/null
+++ b/548/CH4/EX4.18/4_18.sce
@@ -0,0 +1,7 @@
+pathname=get_absolute_file_path('4_18.sce')

+filename=pathname+filesep()+'4_18data.sci'

+exec(filename)

+Po=P*[(y+1)^2*M^2/((4*y*M^2)-2*(y-1))]^3.5*(1-y+2*y*M^2)/(y+1)

+disp("Po=P1*[(y+1)^2*M^2/((4*y*M^2)-2*(y-1))]^3.5*(1-y+2*y*M^2)/(y+1)","pressure measured by pitot tube Po")

+printf("\Answer:\n")

+printf("\n\pressure measured by pitot tube: %f N/m^2\n\n",Po)

diff --git a/548/CH4/EX4.19/4_19.sce b/548/CH4/EX4.19/4_19.sce
new file mode 100755
index 000000000..10721596c
--- /dev/null
+++ b/548/CH4/EX4.19/4_19.sce
@@ -0,0 +1,11 @@
+pathname=get_absolute_file_path('4_19.sce')

+filename=pathname+filesep()+'4_19data.sci'

+exec(filename)

+Ma=[[(Po/Pa)^((y-1)/y)-1]*2/(y-1)]^0.5;disp(Ma,"Ma=","Ma=[(Po/Pa)^((y-1)/y)-1]*2/(y-1)","Mach no at point A")

+Ta=Toa/[1+(y-1)*Ma^2/2];

+disp(Ta,"Ta=","Ta=Toa/[1+(y-1)*Ma^2/2]","static temperature at A")

+Va=sqrt(y*R*Ta)*Ma;

+disp(Va,"Va=","velocity at A =a*Ma,where a(sqrt(y*R*Ta)) is apeed of sound at A")

+printf("\Answer:\n")

+printf("\n\Mach No at A: %f \n\n",Ma)

+printf("\n\velocity at A: %f m/s\n\n",Va)

diff --git a/548/CH4/EX4.20/4_20.sce b/548/CH4/EX4.20/4_20.sce
new file mode 100755
index 000000000..2d375c7eb
--- /dev/null
+++ b/548/CH4/EX4.20/4_20.sce
@@ -0,0 +1,15 @@
+pathname=get_absolute_file_path('4_20.sce')

+filename=pathname+filesep()+'4_20data.sci'

+exec(filename)

+To=Te*A

+disp(To,"To=","To=Te*(1+(y-1)*Me^2/2)","let reservoir temperature required is To ")

+Po=Pe*A^(y/(y-1));

+disp(Po,"Po=","Po=Pe*((1+(y-1)*Me^2/2))^y/y-1","let reservoir pressure required is Po ")

+r=sqrt((2*A/(y+1))^((y+1)/(y-1))/Me^2)

+disp(r,"Ae/At=","Ae/At=sqrt((2*(1+(y-1)*Me^2/2)/(y+1))^((y+1)/(y-1))/Me^2","Area ratio required is equal to")

+printf("\Answer:\n")

+printf("\n\ required reservoir temperature: %f K\n\n",To)

+printf("\n\ required reservoir pressure: %f N/m^2\n\n",Po)

+printf("\n\ required Area Ratio: %f \n\n",r)

+

+

diff --git a/548/CH4/EX4.21/4_21.sce b/548/CH4/EX4.21/4_21.sce
new file mode 100755
index 000000000..7b888a619
--- /dev/null
+++ b/548/CH4/EX4.21/4_21.sce
@@ -0,0 +1,12 @@
+pathname=get_absolute_file_path('4_21.sce')

+filename=pathname+filesep()+'4_21data.sci'

+exec(filename)

+Pstag=Pe*[(y+1)^2*Me^2/((4*y*Me^2)-2*(y-1))]^(y/(y-1))*(1-y+2*y*Me^2)/(y+1)

+disp(Pstag,"Pstag=","Pstag=Pe*[(y+1)*Me^2/((4*y*Me^2)-2*(y-1))]^(y/(y-1))*(1-y+2*y*Me^2)/(y+1)","the stagnation presure is given by Pstag")

+Dstag=Pstag/(R*Tstag);

+disp(Dstag,"Dstag=","Dstag=Pstag/(R*Tstag)","the stagnation density is given by Dstag")

+printf("\Answer:\n")

+printf("\n\ Stagnation temperature: %f K\n\n",Tstag)

+printf("\n\ Stagnation pressure: %f N/m^2\n\n",Pstag)

+printf("\n\ Stagnation density: %f Kg/m^3\n\n",Dstag)

+

diff --git a/548/CH4/EX4.22/4_22.sce b/548/CH4/EX4.22/4_22.sce
new file mode 100755
index 000000000..130e026dd
--- /dev/null
+++ b/548/CH4/EX4.22/4_22.sce
@@ -0,0 +1,9 @@
+pathname=get_absolute_file_path('4_22.sce')

+filename=pathname+filesep()+'4_22data.sci'

+exec(filename)

+Ve=Ae*Me;disp(Ve,"Ve=","velocity at exit Ve=Ae*Me")

+Mt=Dt*At*Vt;disp(Mt,"Mt=Dt*At*Vt","mass flow through nozzle Mt")

+printf("\Answer:\n")

+printf("\n\Velocity at exit: %f m/s\n\n",Ve)

+printf("\n\mass flow through nozzle: %f Kg/m^3\n\n",Mt)

+

diff --git a/548/CH4/EX4.23/4_23.sce b/548/CH4/EX4.23/4_23.sce
new file mode 100755
index 000000000..6949698a0
--- /dev/null
+++ b/548/CH4/EX4.23/4_23.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_23.sce')

+filename=pathname+filesep()+'4_23data.sci'

+exec(filename)

+t=5.2*x/Re^0.5;disp(t,"t=","boundary layer thickness t=5.2*x/Re^0.5")

+D=q*S*Cf;disp(D,"D=","drag on one surface of the plate given by D=q*s*Cf")

+disp(2*D,"Dn=","Net drag Dn is two times both surface i.e 2D")

+printf("\Answer:\n")

+printf("\n\Boundary layer thickness at downstream edge: %f m\n\n",t)

+printf("\n\The drag force on plate: %f N\n\n",2*D)

+

diff --git a/548/CH4/EX4.24/4_24.sce b/548/CH4/EX4.24/4_24.sce
new file mode 100755
index 000000000..3f15b3c0a
--- /dev/null
+++ b/548/CH4/EX4.24/4_24.sce
@@ -0,0 +1,9 @@
+pathname=get_absolute_file_path('4_24.sce')

+filename=pathname+filesep()+'4_24data.sci'

+exec(filename)

+Tw1=q*Cf1;disp(Tw1,"Tw1=","Tw1=q*Cf1","shear stress at 1 cm Tw1:");

+Tw2=q*Cf2;disp(Tw2,"Tw2=","Tw2=q*Cf2","shear stress at 1 cm Tw2:");

+printf("\Answer:\n")

+printf("\n\Local shear stress at 1 cm: %f N/m^2\n\n",Tw1)

+printf("\n\Local shear stress at 5 cm: %f N/m^2",Tw2)

+disp("Hence Tw decreases with distance in flow direction");

diff --git a/548/CH4/EX4.25/4_25.sce b/548/CH4/EX4.25/4_25.sce
new file mode 100755
index 000000000..5b084bf5e
--- /dev/null
+++ b/548/CH4/EX4.25/4_25.sce
@@ -0,0 +1,8 @@
+pathname=get_absolute_file_path('4_25.sce')

+filename=pathname+filesep()+'4_25data.sci'

+exec(filename)

+T=0.37*x/Re^0.2;disp(T,"T=","T=0.37*x/Re^0.2","Thickness at trailing edge T:");

+Df=q*S*Cf;disp(Df,"Df=","Df=q*S*Cf","Drag at top surface")

+printf("\Answer:\n")

+printf("\n\Thickness at trailing edge: %f m\n\n",T)

+printf("\n\Total Drag: %f N",2*Df)

diff --git a/548/CH4/EX4.26/4_26.sce b/548/CH4/EX4.26/4_26.sce
new file mode 100755
index 000000000..a6f53b3a5
--- /dev/null
+++ b/548/CH4/EX4.26/4_26.sce
@@ -0,0 +1,8 @@
+pathname=get_absolute_file_path('4_26.sce')

+filename=pathname+filesep()+'4_26data.sci'

+exec(filename)

+Tw1=q*Cf1;disp(Tw1,"Tw1=","Tw1=q*Cf1","shear stress at 1 cm Tw1:");

+Tw2=q*Cf2;disp(Tw2,"Tw2=","Tw2=q*Cf2","shear stress at 1 cm Tw2:");

+printf("\Answer:\n")

+printf("\n\Local shear stress at 1 cm: %f N/m^2\n\n",Tw1)

+printf("\n\Local shear stress at 5 cm: %f N/m^2",Tw2)

diff --git a/548/CH4/EX4.27/4_27.sce b/548/CH4/EX4.27/4_27.sce
new file mode 100755
index 000000000..60f8a7e8c
--- /dev/null
+++ b/548/CH4/EX4.27/4_27.sce
@@ -0,0 +1,6 @@
+pathname=get_absolute_file_path('4_27.sce')

+filename=pathname+filesep()+'4_27data.sci'

+exec(filename)

+Tw=q*Cf;disp(Tw,"Tw=","Tw=q*Cf","shear stress at point 0.6096 m Tw:");

+printf("\Answer:\n")

+printf("\n\shear stress at a point 0.6096m downstream of the leading edge: %f m\n\n",Tw)

diff --git a/548/CH4/EX4.28/4_28.sce b/548/CH4/EX4.28/4_28.sce
new file mode 100755
index 000000000..214d6c3e4
--- /dev/null
+++ b/548/CH4/EX4.28/4_28.sce
@@ -0,0 +1,10 @@
+pathname=get_absolute_file_path('4_28.sce')

+filename=pathname+filesep()+'4_28data.sci'

+exec(filename)

+Ds=q*S*0.074/Re^0.2;disp(Ds,"Ds=","Ds=q*S*0.074/Re^0.2","turbulent drag over complete area(A+B)");

+Da=q*A*0.074/Ret^0.2;disp(Da,"Da=","Da=q*A*0.074/Ret^0.2","turbulent drag over area A");

+disp(Ds-Da,"Db=","turbulent drag over area B Db:");Db=Ds-Da;

+Dl=q*A*1.328/Ret^0.5;disp(Dl,"Dl=","Dl=q*A*1.328/Ret^0.5","laminar drag over area A");

+Dn=Db+Dl;disp(Dn,"Dn=","Dn=Db+Dl","Net drag Dn")

+printf("\Answer:\n")

+printf("\n\Skin friction Drag over wings of biplane(4 surfaces): %f N\n\n",4*Dn)