Unit 2: Shocks and its applications - Practice Quiz

1 A normal shock wave is oriented at what angle to the approaching flow?

2 What happens to a supersonic flow as it passes through a normal shock?

3 Which static property decreases across a normal shock?

4 Which equation represents conservation of mass across a steady one-dimensional shock?

5 For a steady adiabatic shock with no shaft work, which quantity is conserved by the energy equation?

6 Which conservation law gives across a normal shock?

7 What does the Hugoniot equation relate across a shock wave?

8 On a pressure-specific-volume diagram, what does the Hugoniot curve represent?

9 In which reference frame does a stationary normal shock have zero propagation speed?

10 Which device commonly produces a moving normal shock wave?

11 Which engineering system may use a normal shock to slow supersonic flow?

12 An attached oblique shock commonly forms when supersonic flow encounters which feature?

13 Which velocity component is used in the normal-shock relations for an oblique shock?

14 For an inviscid oblique shock, what happens to the tangential velocity component?

15 Why can an oblique shock reflect from a solid wall?

16 What may occur when two oblique shock waves meet?

17 In a regular shock reflection, which waves meet at the wall?

18 Which quantity is normally continuous across a slip line in inviscid flow?

19 What pressure condition does a shock usually impose on a boundary layer?

20 A strong shock-boundary layer interaction can cause which flow phenomenon?

21 A supersonic flow passes through a sequence of increasingly strong compression waves in a converging region. Why can these waves develop into a normal shock?

22 For air with , a normal shock forms at an upstream Mach number of . What is the approximate density ratio ?

23 A stationary normal shock occurs in an adiabatic, constant-area duct with no shaft work. Which property remains constant across the shock?

24 Air with enters a normal shock at . Using the normal-shock relation, what is the approximate downstream Mach number?

25 Which expression represents the Hugoniot energy relation between states 1 and 2, where is specific volume?

26 On a pressure-specific-volume diagram, how is the physically possible downstream shock state determined for a specified upstream state and mass flux?

27 Gas moves to the right at while a normal shock moves to the left at . If the upstream sound speed is , what is the upstream Mach number relative to the shock?

28 A normal shock travels at into stationary air whose sound speed is . What upstream Mach number is observed in the shock-fixed frame?

29 A normal shock stands ahead of a blunt body in supersonic flight. Which change occurs as the flow crosses the shock?

30 For air at , an oblique shock has a shock angle . What is the approximate pressure ratio ?

31 For a fixed supersonic upstream Mach number, the wedge deflection angle is increased while remaining below the maximum angle for an attached weak shock. What generally happens?

32 At , the Mach angle is . Which shock angle can represent an attached compression shock?

33 An oblique shock strikes a straight solid wall in a regular reflection. What is the main role of the reflected shock?

34 When regular reflection cannot satisfy the required turning and pressure conditions, which pattern commonly develops?

35 Two equal oblique shocks generated by symmetric compression corners meet on the duct centerline. What flow pattern is expected immediately after their symmetric interaction?

36 Two unequal oblique shocks intersect, producing downstream regions that initially have different pressures and flow directions. What structure commonly completes the interaction?

37 Which set of conditions is appropriate across an inviscid slip line?

38 Why is there no mass flow across a steady slip line even though the velocities on its two sides may differ?

39 A strong shock imposes a rapid pressure rise on a boundary layer. Which response is most likely if the boundary layer has insufficient momentum?

40 Why can the pressure rise from a shock influence the boundary layer upstream of the nominal shock location?

41 A finite-amplitude one-dimensional compression disturbance propagates into initially uniform gas. Which mechanism causes it to evolve into a normal shock?

42 Air with passes through a stationary normal shock at . Which set of downstream ratios and Mach number is correct?

43 For a calorically perfect gas with , the measured Mach number immediately behind a normal shock is . What was the upstream Mach number?

44 Let denote specific volume. For a calorically perfect gas, which pressure-volume relation represents the shock Hugoniot through state 1?

45 States 1 and 2 lie on both a Rayleigh line and the shock Hugoniot. If the mass flux through the shock is , which expression follows from momentum conservation?

46 A normal shock moves at speed into stationary air with . What is the gas velocity immediately behind the shock in the laboratory frame?

47 An ideal Pitot probe is placed in an air stream at with . Accounting for the detached normal shock ahead of the probe, what pressure ratio does it approximately measure relative to upstream static pressure?

48 A weak oblique shock in air has and shock angle . Which pair most closely gives the flow deflection and downstream Mach number?

49 A two-dimensional compression corner turns a Mach 2 air stream through . Assuming , what shock structure should be expected near the corner?

50 For a deflection below , weak and strong oblique-shock solutions exist at the same upstream Mach number. Which comparison is generally correct?

51 An incident oblique shock turns a supersonic flow toward a straight wall. Which condition is required for regular reflection from that wall?

52 As the incidence angle increases, regular reflection transitions to Mach reflection. Which feature distinguishes the Mach-reflection configuration?

53 A fixed total compression turn is produced either by one oblique shock or by several weaker oblique shocks with intermediate flow alignment. In the weak-shock limit, which arrangement best preserves stagnation pressure?

54 Two oblique shocks intersect, producing different shock sequences on the two sides of a downstream discontinuity. What compatibility conditions must the final states satisfy along that discontinuity?

55 In a shock-polar construction for the interaction of two supersonic streams, what does a physically admissible intersection of the downstream shock polars represent?

56 For an inviscid stationary slip line, which set of quantities is constrained to be continuous across the line?

57 Two streams originate from the same uniform calorically perfect gas and pass through unequal adiabatic shock sequences before meeting at a slip line. Which statement is correct?

58 During shock-induced boundary-layer separation, which local condition most directly identifies incipient separation at the wall?

59 Why can a compression-induced pressure rise influence a turbulent boundary layer upstream of the nominal shock impingement point even when the external stream is supersonic?

60 A strong shock impinges on a boundary layer and creates a separated region with a characteristic -shock pattern. What primarily forms the upstream leg of this pattern?