//Example 7_10 clc;clear; // Given values L_m=0.991;// Length of the model truck in m h_m=0.257;// Height of the model truck in m w_m=0.159;// Width of the model truck in m V_p=26.8;// Velocity of the prototype in m/s T=25;// °C C=16;// Geometric ratio // Properties //For air at atmospheric pressure and at T=25°C, rho_m=1.184;// Density of air in kg/m^3 mu_m=1.849*10^-5;// Viscosity of air in kg/m.s // Calculation // From table 7.7, V_m=[20 25 30 35 40 45 50 55 60 65 70];// Velocity of the model truck in m/s F_D=[12.4 19.0 22.1 29.0 34.3 39.9 47.2 55.5 66.0 77.6 89.9];// Drag force of the model truck in N for(i=1:11) A_m=w_m*h_m;// Area of the model truck in m^2 C_Dm(i)=(F_D(i))/((1/2)*rho_m*(V_m(i))^2*A_m);// Drag coefficient Re_m(i)=(rho_m*V_m(i)*w_m)/(mu_m);// Reynolds number of the model truck end xlabel('Re*10^-5'); ylabel('C_D'); xtitle('FIGURE 7-41'); plot((Re_m/10^5),C_Dm,'o'); rho_p=rho_m;// Density of air in kg/m^3 w_p=w_m;// Width of the prototype in m mu_p=mu_m;// Viscosity of air in kg/m.s Re_p=(rho_p*V_p*w_p)/(mu_p);// Reynolds number of the prototype A_p=A_m;// // Area of the prototype in m^2 C_Dp=C_Dm(10);// Drag coefficient F_Dp=(1/2)*rho_p*V_p^2*C^2*A_p*C_Dp;// Aerodynamic drag on the prototype in N printf("The aerodynamic drag on the vehicle=%0.0f N\n",F_Dp); // The answer provided in the textbook is wrong