Question

For which of 'water' flow velocities at 200C can we assume that the flow is incompressible ? a.1000 km per hour b. 500 km per hour c. 2000 km per hour d. 200 km per hour

Answer 1

Answer:d

Step-by-step explanation:

Given

Temperature
`=200^(\circ)\approc 473 K`

Also
`\gamma for air=1.4`

R=287 J/kg

Flow will be In-compressible when Mach no.<0.32

Mach no.
`=(V)/(√(\gamma RT))`

(a)
`1000 km/h\approx 277.78 m/s`

Mach no.
`=(277.78)/(√(1.4* 287* 473))`

Mach no.=0.63

(b)
`500 km/h\approx 138.89 m/s`

Mach no.
`=(138.89)/(√(1.4* 287* 473))`

Mach no.=0.31

(c)
`2000 km/h\approx 555.55 m/s`

Mach no.
`=(555.55)/(√(1.4* 287* 473))`

Mach no.=1.27

(d)
`200 km/h\approx 55.55 m/s`

Mach no.
`=(55.55)/(√(1.4* 287* 473))`

Mach no.=0.127

From above results it is clear that for Flow at velocity 200 km/h ,it will be incompressible.