## How is stagnation property calculated?

The values of pressure,temperature and density at that point represent as stagnation pressure, stagnation temperature and stagnation density.

- Data : Speed of airplane V=900kmph=900×100060×60=250m/s.
- ps=p1(1+k−12×m21)kk−1.
- =8×104(1+1.4−12×0.7762)
- Ts=T1(1+k−12×M21)
- =258×(1+1.4−12×0.7762)
- ∴ρs=11.91×104287×289.07=1.43kg/m3.

## What is the stagnation reference condition?

The thermodynamic state which would exist at a point in a fluid stream (stagnation point) if the flow at that point was brought isentropically to rest.

**What do you mean by stagnation properties?**

The stagnation properties at a point are defined as those which are to be obtained if the local flow were imagined to cease to zero velocity isentropically. As we will see in the later part of the text, stagnation values are useful reference conditions in a compressible flow.

**What is stagnation pressure equation?**

The Bernoulli equation applicable to incompressible flow shows that the stagnation pressure is equal to the dynamic pressure plus static pressure. Total pressure is also equal to dynamic pressure plus static pressure so, in incompressible flows, stagnation pressure is equal to total pressure.

### What is the Mach number at the stagnation point?

Mach 3

At the lower Mach numbers, below Mach 3, the values of stagnation temperature are the same, because the temperature is not high enough to excite the vibrational modes. But beginning around Mach 3, real gas effects become increasingly important with increasing Mach number.

### How is stagnation enthalpy calculated?

When the potential energy of the fluid is negligible, the stagnation enthalpy represents the total energy of a flowing fluid stream per unit mass. Stagnation enthalpy is the sum of the enthalpy associated with the temperature at each point plus the enthalpy associated with the dynamic pressure at each point.

**Why do we use stagnation properties?**

The stagnation temperature is important because it is the temperature that occurs at a stagnation point on the object. Because the total temperature does not change through a shock wave, the stagnation temperature and and the total temperature have the same value at a stagnation point.

**What is the characteristic of stagnation point?**

Explanation: Stagnation point is the point in fluid mechanics where the velocity of the fluid at that point is zero. Stagnation points occur at places where the fluid is brought to a state of rest by an object. They usually exist at the surface of objects.

#### Is stagnation enthalpy constant?

It is understood that all stagnation properties are constant along an isentropic flow. If such a flow starts from a large reservoir where the fluid is practically at rest, then the properties in the reservoir are equal to the stagnation properties everywhere in the flow (Fig. 18.1).