Answer:
Mach number = 0.68168
The flow should be treated as compressible.
Explanation:
Given that:
The altitude of a commercial jet = 35000
The properties of air at that given altitude are as follows:
Pressure = 24.577 kPa
Temperature T = 50.78176° C
Temperature T = ( 50.78176 + 273 )K = 328.78176 K
[tex]\varphi = 0.38428 \ kg/m^3[/tex]
The velocity is also given as: 550 mph = 245.872 m/s
Therefore, the sonic velocity is firstly determined by using the formula:
[tex]a = \sqrt{ \vartheta \times R \times T\[/tex]
[tex]a = \sqrt{1.4 \times 287 \times 323.78176[/tex]
[tex]a = \sqrt{130095.5112[/tex]
a = 360.68755 m/s
Then, we can calculate the Mach number by using the expression:
[tex]{Mach \ number = \dfrac{V}{a}}[/tex]
[tex]Mach \ number = \dfrac{245.872}{360.68755}[/tex]
Mach number = 0.68168
b) Ideally, all flows are compressible because the Mach number is greater than 0.3, suppose the Mach number is lesser than 0.3, then it is incompressible.
