09/20

Reading verification:

1.

Write mass conservation across a steady normal shock wave.

2.

What stagnation (or total) quantities are the same at both sides of a shock wave for any gas?

h_t

3.

What stagnation quantities are also the same for a perfect gas?

T_t, a_t

4.

Weak shocks

(a)

em move through the gas with approximately the speed of sound.

(b)

are approximately isothermal.

(c)

are approximately isenthalpic.

(d)

are approximately steady.

5.

Weak shocks

(a)

have equal flow velocity before and behind them.

(b)

are approximately isentropic.

(c)

have a slightly greater stagnation enthalpy behind them than before them since the gas is slighty heated.

6.

The ratio of a stagnation quantity to the corresponding critical quantity

(a)

is equal to one: they are the same thing.

(b)

is a fixed number that is the same for all perfect gases.

(c)

is a fixed number for a given perfect gas, but may be different for another perfect gas.

(d)

depends on the Mach number as well as on the properties of the perfect gas.