9.3 Air is approaching a converging-diverging nozzle with a low velocity at 20 °C and 85 kPa, and it leaves the nozzle at a supersonic velocity. The velocity of air at the throat of the nozzle is
A: 82 m/s
B: 98 m/s
C: 313 m/s
D: 343 m/s
A: 82 m/s
B: 98 m/s
C: 313 m/s
D: 343 m/s
举一反三
- A compressible fluid is flowing through a pipe with a constriction. The diameter of the narrow section is 1/2 the diameter of the wide section. The density of the fluid in the narrow section is 3/4 the density of the fluid in the wide section. If the velocity of the compressible fluid is 3.600 m/s in the narrow section, then what is the velocity of the fluid in the wide section? A: 0.675 m/s B: 0.805 m/s C: 0.250 m/s D: 0.333 m/s E: 0.500 m/s
- A rock is thrown straight up with an initial velocity of 15.0 m/s. Ignore energy lost to air friction. How high will the rock rise? A: 1.53 m B: 22.9 m C: 6.50 m D: 11.5 m
- 雷诺数取决于下列哪些因素( ) A: 特征尺寸Lc(characteristic length, m) B: 流体密度(fluid density, kg/m3) C: 特征速度V(velocity of the bulk fluid, m/s) D: 流体的动力粘度μ(dynamic viscosity, kg/m·s)
- A rock is thrown straight up with an initial velocity of 15.0 m/s. Ignore energy lost to air friction. How high will the rock rise? A: 1.53 m B: 22.9 m C: 6.50 m D: 11.5 m E: 13.5 m F: 15.7 m G: 21.5 m H: 17.5 m
- 管子中流体和气体的流速一般不超过（ ）。 A: 5 m/s，50 m/s B: 3 m/s，30 m/s C: 3 m/s，100 m/s D: 10 m/s，100 m/s