Normal Shock
50 questions available
Questions
What are the four primary equations used to describe the conditions across a normal shock for a perfect gas?
View answer and explanationWhat fundamental principle dictates that a normal shock wave can only proceed from a supersonic flow (Mx > 1) to a subsonic flow (My < 1)?
View answer and explanationHow does the total temperature (T0) of a perfect gas change across a stationary normal shock?
View answer and explanationAccording to the Rankine-Hugoniot relation for a normal shock, what is the downstream Mach number (My) squared, as a function of the upstream Mach number (Mx) squared and the specific heat ratio (k)?
View answer and explanationFor a normal shock in a perfect gas with k=1.4, if the upstream Mach number (Mx) is 3.0, what is the approximate ratio of downstream pressure to upstream pressure (Py/Px)?
View answer and explanationWhat is Prandtl's condition for a normal shock, relating the upstream velocity (U1), downstream velocity (U2), and the critical speed of sound (c*)?
View answer and explanationAs the upstream Mach number (Mx) of a normal shock becomes very large (approaches infinity), what is the limiting value of the downstream Mach number (My)?
View answer and explanationHow is the analysis of a moving shock wave, such as one created by a suddenly closed valve, typically simplified?
View answer and explanationIn the analysis of a moving shock created by a valve suddenly stopping a flow, what is the 'upstream' Mach number in the moving coordinate system (Mx') if the original flow Mach number was Mx and the shock Mach number is Msx?
View answer and explanationWhat happens to the total pressure (P0) of a gas as it passes through a normal shock?
View answer and explanationThe strength of a weak normal shock is defined by the dimensionless pressure rise, P-hat = (Py - Px) / Px. How is P-hat related to the upstream Mach number (Mx) for small perturbations?
View answer and explanationA gas flowing at a Mach number of 0.4 is brought to a partial stop by closing a valve, such that the Mach number behind the shock is 0.2. What type of problem does this scenario represent?
View answer and explanationIn a shock tube, what are the conditions in zone 2, the region immediately behind the moving shock front?
View answer and explanationWhat is the relationship between the density ratio (rho_y/rho_x) and the velocity ratio (Ux/Uy) across a normal shock?
View answer and explanationIn a reflective shock from a suddenly closed valve, a gas flow at a prime Mach number Mx' of 1.2961 is brought to a complete stop (My' = 0). For k=1.4, what is the resulting pressure ratio (Py/Px) of the shock?
View answer and explanationWhy are two solutions (intersections) obtained when plotting Fanno flow and Rayleigh flow curves on a T-s diagram?
View answer and explanationWhat is the relationship for the density ratio (rho_y/rho_x) across a normal shock as a function of the upstream Mach number (Mx) and specific heat ratio (k)?
View answer and explanationWhen a piston moves into a still gas, it creates a moving shock. The analysis involves a 'strange' Mach number, Myx', which is defined as what?
View answer and explanationWhat is the primary reason for the total pressure loss across a normal shock?
View answer and explanationIn the analysis of a moving shock in a stationary medium (suddenly open valve), the stagnation temperature in stationary coordinates rises. Why does this occur?
View answer and explanationFor a shock moving at 450 m/sec into stagnant air at 300 K (k=1.3, R=287 J/kgK), the calculated prime Mach number My' is approximately 1.296. What is the corresponding stationary upstream Mach number (Mx) for this shock?
View answer and explanationWhat is the relationship between the temperature ratio (Ty/Tx) and the pressure ratio (Py/Px) across a normal shock?
View answer and explanationIn the shock tube diagram (Figure 5.16), what separates zone 2 (shocked gas) from zone 3 (expanded driver gas)?
View answer and explanationA shock is moving into a stationary medium. If the specific heat ratio is k=1.4, what is the theoretical maximum possible Mach number of the gas behind the shock (My') in the stationary frame?
View answer and explanationFor a gas with k=1.4, what is the minimum upstream Mach number (Mx) required to create a normal shock?
View answer and explanationWhat physical assumption allows the thickness of a normal shock to be considered very small or negligible in the governing equations?
View answer and explanationIn the analysis of a moving shock into stationary medium from a suddenly opened valve, how is the shock Mach number ahead of the shock (Msx) defined?
View answer and explanationFor a normal shock with an upstream Mach number of 2.0 and k=1.4, what is the total pressure ratio P0y/P0x?
View answer and explanationWhat is assumed about chemical reactions, such as condensation, within the very narrow width of a normal shock in the simplified model?
View answer and explanationWhat does the star Mach number, M*, represent?
View answer and explanationA gas is flowing in a pipe with a Mach number of 0.4. A valve is closed such that the Mach number is reduced by half to 0.2. What is the approximate stationary Mach number (Mx) of the shock wave generated, assuming k=1.4?
View answer and explanationIn the momentum equation for a normal shock, Px - Py = rho_y * Uy^2 - rho_x * Ux^2, what physical principle does this equation represent?
View answer and explanationFor a shock moving into still air (Mx'=0), how is the downstream Mach number in the moving frame (My') related to the shock Mach number (Msy)?
View answer and explanationWhat is the primary characteristic of the 'contact surface' in a shock tube?
View answer and explanationIf a piston accelerates very rapidly in a tube of air at 300 C with M=0.4, and the air next to the piston reaches M=0.8, what is the approximate speed of the shock wave created? The speed of sound in the undisturbed air is 347.2 m/s and k=1.4.
View answer and explanationWhat does the dimensionless group M*1 * M*2 equal, according to Prandtl's condition?
View answer and explanationIn the industrial problem presented in Example 5.10, a valve is opened between a 30 Bar reservoir and a pipe leading to a 1 Bar ambient condition. What phenomenon limits the initial flow characteristics?
View answer and explanationIf a normal shock occurs with an upstream Mach number of 4.0 in a gas with k=1.4, what is the approximate downstream Mach number (My)?
View answer and explanationWhat is the primary difference in the stagnation temperature change between a stationary shock and a moving shock (viewed from a stationary frame)?
View answer and explanationIn order to double the temperature across a reflective shock from a suddenly closed valve (Ty/Tx = 2.0), what must be the stationary Mach number (Mx) of the shock, assuming k=1.4?
View answer and explanationWhat does a value of P0y/P0x = 1.0 signify for a flow process?
View answer and explanationIf two pistons in a 1-meter long tube move toward each other, one creating a shock with Us=1.0715*c and the other Us=1.1283*c, where c=347 m/s, approximately how long will it take for the shocks to collide?
View answer and explanationWhich statement accurately describes the change in static properties across a normal shock?
View answer and explanationWhat is the key simplification that allows the Fanno flow and Rayleigh flow models to be used in analyzing a normal shock?
View answer and explanationFor a shock moving into a stationary medium with k=1.3, what is the maximum possible Mach number of the gas behind the shock (My')?
View answer and explanationAccording to Figure 5.3, how does the total pressure ratio (P0y/P0x) change as the upstream Mach number (Mx) increases from 1 to 10?
View answer and explanationIf a shock has a static pressure ratio (Py/Px) of 6.317 and a temperature ratio (Ty/Tx) of 2.0, what was the approximate upstream prime Mach number (Mx') of the flow before it was stopped by a valve, for a gas with k=1.4?
View answer and explanationThe relationship My^2 = (Mx^2 + 2/(k-1)) / ( (2k/(k-1))Mx^2 - 1 ) is described as a 'symmetrical equation'. What does this symmetry imply?
View answer and explanationIn the general case of a moving shock where a gas flows into another gas with a different velocity (partially open valve), what additional parameter must be supplied to solve the problem, compared to a shock in a stationary medium?
View answer and explanationWhat is the physical interpretation of the 'shock-choking' phenomenon?
View answer and explanation