zcm
Question 3
A piston compresses gas in a cylinder at constant speed V = 15 m/s. At one instant when the piston is at Lo =
0.14 m away from the closed end of the cylinder, the gas density Po = 18 kg/m³. The gas velocity varies
linearly from V at the piston to zero at the closed end. Determine (1) an expression for the average gas
density as a function of time, and (2) the rate of change of gas density at this instant. Use the continuity
equation. Assume the gas in the cylinder is unsteady, uniform, 1-D, and compressible.
V = constant
u(x, 1)
p(1)
x=0
x = L(t)
Formulas