Homework 1
Due : 6th April (24:00)
Assistant: 오세훈 osh6547@gmail.com
Homework format
ECH2031: Computational Methods in Chemical Engineering
HW1
John 2111111119 (as shown in your Student ID card)
Q1.
Q2.
1. Rather than the linear relationship FU = - cv, you might choose to model the
upward force on the parachutist as a second order relationship.
FU = - c’ v2
Where c’ = a second-order drag coefficient (kg/m).
Use a value of c’=0.225 kg/m, g=9.8m/s2, m=68.1kg.
The analytical solution for the case where the jumper is initially at rest (v = 0 at t
= 0) is as a follow.
v=
gc'
gm
tanh
t
m
c'
(a) Obtain the numerical solution and plot it from t=0 to t=20 with the same
initial condition and parameter values. (Hint: Use EXCEL)
(b) Plot above two solutions together and calculate the percent relative error of
the velocity at t=6.
Note: A copy of EXCEL calculation sheet also needs to be submitted.
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