Freestream pressure for a Mach 4 supersonic windtunnel is 1949 Pa when expanded from a reservoir...

Freestream pressure for a Mach 4 supersonic windtunnel is 1949 Pa when expanded from a reservoir pressure of 3 bar. Calculate the pressure at the face of a pitot tube placed in such a facility. Why is the gas at rest on the Pitot tube face at a lower pressure than the gas at rest in the reservoir?

Expert Solution

Given static pressure P = 1949 Pa, M =4, gamma = 1.4 (for air)

From isentropic relations,

P₀ = 295926.8392 Pa

Given Reservoir P_0r = 3 bar = 300000 Pa.

We can see the loss of total pressure from reservoir to freestream inlet. In supersonic windtunnel, to increase the mach number we have a vacuum chamber at the end of the tunnel. So, the incoming flow has to expand from really high pressure to really low pressure. From the Thermodynamics we know that as pressure decreases the temperature also decreases and this process takes place while in contact with the atmosphere from outer wall of the wind tunnel. So, this process results in a irreversible process. Irreversibel process results into loss of energy of the fluid which leads to loss of total pressure.

genius_generous answered 2 years ago

5. (IB) An ideal gas at an initial pressure of 4.0 × 105 Pa is expanded...

5. (IB) An ideal gas at an initial pressure of 4.0 × 105 Pa is expanded isothermally from a volume of 3.0 m3 to a volume of 5.0 m3. a) Calculate the final pressure of the gas. b) On graph paper, sketch a graph to show the variation with volume V of the pressure p during this expansion. c) Use the sketch graph in (b) to: (i) estimate the work done by the gas during this process (ii) explain why...

Air is supplied to a convergent–divergent nozzle from a reservoir where the pressure is 100 kPa....

Air is supplied to a convergent–divergent nozzle from a reservoir where the pressure is 100 kPa. The air is then discharged through a short pipe into another reservoir where the pressure can be varied. The cross-sectional area of the pipe is twice the area of the throat of the nozzle. Friction and heat transfer may be neglected throughout the flow. If the discharge pipe has constant cross-sectional area, determine the range of static pressure in the pipe for which a...

I compress an ideal gas under a constant pressure of 3.2 × 105 Pa from 6.31...

I compress an ideal gas under a constant pressure of 3.2 × 105 Pa from 6.31 mL to 5.12 mL. i. What is the work done in this process? ii. If this is an adiabatic process, what is q and ∆U for this process?

When a drop of water falls into a reservoir of water from a high enough altitude,...

When a drop of water falls into a reservoir of water from a high enough altitude, water droplets will splash Does the water in those droplets come from the original drop or from the reservoir?

2.50 mole of perfect gas at 0°C is expanded from an initial pressure of 5.00 atm...

2.50 mole of perfect gas at 0°C is expanded from an initial pressure of 5.00 atm to a final pressure of 1.00 atm against a constant external pressure of 1.00 atm. (a) isothermally and (b) adiabatically. (1) Calculate the values of q, w, DU, DH, DS, DSsur and DStot for (a) and (b) (2) Draw p -V diagram to represent these two different paths.

Starting from volume VA and pressure PA, an ideal gas undergoes the following three-stage, reversible, cyclic...

Starting from volume VA and pressure PA, an ideal gas undergoes the following three-stage, reversible, cyclic process: (i) adiabatic expansion to volume VB, then (ii) isochoric heating to pressure PA, then (iii) isobaric cooling to volume VA. Draw this process on a P V -diagram, and evaluate the change in the entropy of the system (∆S), for each stage. Show that the sum of these entropy changes is zero, as it should be since the system returns to its initial...

A mole of air is sampled from the atmosphere when the atmospheric pressure is 765 mm...

A mole of air is sampled from the atmosphere when the atmospheric pressure is 765 mm Hg, the temperature is 25 C, and relative humidity is 75%. The sample of air is placed inside a closed container and heated to 135 C and then compressed to 2 atm. What are the relative humidity, the humidity, and the mole fraction of water in the compressed air?

A mole of air is sampled from the atmosphere when the atmospheric pressure is 765 mmHg,...

A mole of air is sampled from the atmosphere when the atmospheric pressure is 765 mmHg, the temperature is 25 C, an relative humidity is 75%. The sample of air is placed inside a closed container and heated to 135 C and then compressed to 2 atm. What are the relative humidity, the humidity, and the mole fraction of water in the compressed air?

How does blood pressure respond when an individual moves from a supine to a standing position?...

How does blood pressure respond when an individual moves from a supine to a standing position? What causes this response? What is the name of this phenomenon? Describe the typical systolic and diastolic blood pressure responses to exercise of increasing intensity. Describe the four general indications for stopping an exercise test. Explain the typical changes in blood pressure and cardiac output following intense exercise. Why do these changes make it necessary to perform a cooldown period after intense exercise? Describe...

4. Calculate the income-elasticity of demand for a product, when income rises from $ 18,000 to...

4. Calculate the income-elasticity of demand for a product, when income rises from $ 18,000 to $ 20,000, while demand decreases from 28,000 to 26,000. Sort the good. I. Identification of variables I1= Q1= I2= Q2= II. Get the changes ▲Q = ▲I= III. Get the averages _ Q= _ I = .Calculate EID and classify the good =

Question