Speed of Sound
50 questions available
Questions
What is the fundamental relationship that defines the square of the speed of sound, c, in terms of the rate of change of pressure (P) with respect to density (ρ)?
View answer and explanationFor a perfect gas, what is the correct formula for the speed of sound, c, given the ratio of specific heats (k), the specific gas constant (R), and the absolute temperature (T)?
View answer and explanationIn the context of a two-phase medium, such as gas with dust particles, how does the addition of the second phase (particles) affect the speed of sound compared to that of the pure gas?
View answer and explanationFor calculating the speed of sound in liquids, the formula c = sqrt(B/ρ) is used. What does the term 'B' represent?
View answer and explanationCalculate the speed of sound in air at a temperature of 300 Kelvin. Assume air is a perfect gas with a ratio of specific heats (k) of 1.4 and a specific gas constant (R) of 287 J/(kg·K).
View answer and explanationThe equation of state for a real gas can be expressed as P = zρRT. What does the compressibility factor, 'z', represent?
View answer and explanationAccording to the text, how does the speed of sound in solids generally compare to the speed of sound in liquids and gases?
View answer and explanationThe derivation of the speed of sound from a pressure pulse (Figure 3.1) assumes the flow process is of what nature?
View answer and explanationIn a two-phase mixture of gas and solid particles, the effective ratio of specific heats, γ, is given by the formula (Cp + mC) / (Cv + mC). What does the term 'm' represent in this context?
View answer and explanationUsing the provided information, what is the approximate speed of sound in distilled water at 25 degrees Celsius?
View answer and explanationWhat physical property of a solid is used in the formula c = sqrt(E/ρ) to represent its elastic properties for calculating the speed of sound?
View answer and explanationCalculate the speed of sound in a solid structural steel with a Young's Modulus (E) of 160 x 10^9 N/m^2 and a density (ρ) of 7860 Kg/m^3.
View answer and explanationThe derivation for the speed of sound c^2 = dP/dρ can be obtained from the energy equation. What other fundamental equation can also be used to derive the same result?
View answer and explanationWhen calculating the speed of sound in a real gas, the coefficient 'n' is used in the relation P/ρ^n = constant. The text defines n as k * [(z + T(∂z/∂T)ρ) / (z + T(∂z/∂T)P)]. Under what condition does 'n' approach the value of 'k'?
View answer and explanationWhy is it important for engineers to understand the speed of sound in non-pure substances, such as air with particles, as highlighted in the Motivation section of the chapter?
View answer and explanationWhich of the following substances listed in Table 3.3 has the highest speed of sound?
View answer and explanationThe speed of sound in a real gas can be calculated as c = sqrt(znRT). An engineer is working with air at 30 degrees Celsius and atmospheric pressure, for which k=1.407, z=0.995, and n=1.403, with R=287 J/kg/K. What is the approximate speed of sound?
View answer and explanationIn a mixture of gas with a small amount of liquid droplets, the mixture isentropic relationship is given as P * T^((1-γ)/γ) = constant. How is the effective gamma (γ) for the mixture defined?
View answer and explanationWhat is the average bulk modulus of water given as an example in the text?
View answer and explanationWhen analyzing a two-phase mixture, the text assumes that the two materials are homogeneously mixed and that two other transport phenomena do NOT occur between the particles. What are these two phenomena?
View answer and explanationWhich liquid listed in Table 3.2 has the lowest speed of sound?
View answer and explanationIn the derivation of the speed of sound, a control volume is attached to a pressure pulse. What is the velocity of the gas entering the control volume from the right, relative to the control volume itself?
View answer and explanationThe speed of sound in a perfect gas is given by c = sqrt(kRT). If the temperature of the gas is quadrupled, how does the new speed of sound compare to the old one?
View answer and explanationWhat is the primary reason that a correction factor 'z' (compressibility factor) is needed for real gases but not for ideal gases?
View answer and explanationThe speed of sound is generally defined in physical terms as the square root of the ratio of two properties of the medium. What are these two properties?
View answer and explanationWhich of the following materials listed in Table 3.3 has a speed of sound closest to 5100 m/s?
View answer and explanationWhat is the main reason provided in the text for the limited discussion about the speed of sound outside of ideal gases in traditional compressible flow classes?
View answer and explanationIn the analysis of a two-phase medium, what does the approximation ρ/ρ_a = 1 + m apply to?
View answer and explanationWhat happens to the correction factor in Example 3.3 for the time it takes sound to travel through a linearly varying temperature field as the temperature difference between points A and B approaches zero (TB -> TA)?
View answer and explanationIn summary, the text states that the speed of sound in liquids is about how many times relative to the speed of sound in gases?
View answer and explanationWhen analyzing the speed of sound for a real gas, which thermodynamic function is used to begin the derivation that relates enthalpy, entropy, and pressure (Tds = dh - dP/ρ)?
View answer and explanationWhat is the speed of sound in rubber as listed in Table 3.3?
View answer and explanationIn Example 3.2, the speed of sound in water vapor at 20 bar and 350 degrees C is calculated. The ideal gas assumption yields a result of 771.5 m/sec. How does this compare to the value estimated from the steam tables?
View answer and explanationFor a two-phase mixture of gas and solid particles, the effective gas constant for the mixture, R_mix, is implicitly defined by the equation P/ρ = R_mix * T. How does R_mix relate to the gas constant of the pure gas, R?
View answer and explanationWhat is the general trend for the speed of sound in fresh water as the temperature increases from 0 degrees Celsius to 34 degrees Celsius?
View answer and explanationWhat is the key assumption made about the pressure pulse in the derivation of the speed of sound?
View answer and explanationThe text mentions Wilson's empirical formula for the speed of sound in sea water, c(S, T, P). What three parameters does this formula depend on?
View answer and explanationAccording to the analysis in Section 3.4, a change in which property can have a 'dramatical change' on the speed of sound for a real gas, especially at moderate pressure but low temperature?
View answer and explanationIn the analysis of a two-phase medium like gas with dust, the equation P/ρ_a^k = constant is used. What does ρ_a represent?
View answer and explanationWhat is the primary physical reason the situation with sound speed in solids is 'considerably more complicated' than in liquids or gases?
View answer and explanationWhich of the following materials from Table 3.3 has a speed of sound value for its longitudinal wave of 5790 m/s?
View answer and explanationFor an ideal gas, the pressure can be expressed as P = constant * ρ^k. What does this relationship describe?
View answer and explanationWhat is the speed of sound in Mercury as listed in Table 3.2?
View answer and explanationAt what condition does the compressibility factor 'z' in Figure 3.3 equal 1?
View answer and explanationWhy does the text state that 'one language is not enough today' in a footnote in the motivation section?
View answer and explanationWhat is the speed of sound in Glycerol as listed in Table 3.2?
View answer and explanationThe text states that the speed of sound in a solid is dependent on geometry and can have different values for transverse and longitudinal waves. For steel, what is the speed of the transverse shear wave listed in Table 3.3?
View answer and explanationIn the analysis of sound speed in a two-phase medium, what does the variable ξ (xi) represent?
View answer and explanationCalculate the speed of sound in a liquid with a bulk modulus (B) of 2.2 x 10^9 N/m^2 and a density (ρ) of 1000 kg/m^3.
View answer and explanationIn the derivation of the speed of sound from a moving piston, what term is neglected in Equation (3.3) to arrive at Equation (3.4)?
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