f13_sp

# f13_sp - Fluids – Lecture 13 Notes 1 Stagnation...

This preview shows pages 1–2. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Fluids – Lecture 13 Notes 1. Stagnation Quantities 2. Introduction to Shock Waves Reading: Anderson 7.5, 7.6 Stagnation Quantities Adiabatic stagnation processes An adiabatic stagnation process is one which brings a moving ﬂuid element to rest adiabat- ically (without heat addition or removal). The figure a ﬂuid element at station 1 in some ﬂow being brought to rest by two hypothetical adiabatic processes. Process A is done by placing a blunt object in the ﬂow, such that the ﬂuid element reaches the stagnation point, where V = 0. Process B lets the ﬂuid element ﬂow into a large insulated chamber where it will mix with the stationary ﬂuid there and thus come to rest. 1 h 1 V h 1 h 1 V 1 h 1 V Adiabatic Process A Adiabatic Process B stag stag V =0 h stag stag V =0 Actual Flow The changes of h and V for either process are governed by the total enthalpy relation 1 h o ≡ h + V 2 = constant 2 derived previously. Therefore, we have 1 1 2 h o 1 ≡ h 1 + V 1 2 = h stag + 2 V stag = h stag 2 We see that at the end of the stagnation process, h stag is equal to the total enthalpy h o 1 at the beginning. For this reason, the terms stagnation enthalpy and total enthalpy are largely synonymous, although they are two distinct concepts. The total enthalpy h o on the streamline can therefore be measured by setting up an actual stagnation process, typically with a small obstruction like a small-scale version of Process A, and measuring the resulting temperature T stag . One can then calculate h o = h stag = c p T stag ....
View Full Document

## This note was uploaded on 01/28/2012 for the course AERO 16.01 taught by Professor Markdrela during the Fall '05 term at MIT.

### Page1 / 4

f13_sp - Fluids – Lecture 13 Notes 1 Stagnation...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online