Compressible Flow

Syllabus

Course Meeting Times

Lectures: 2 sessions / week, 1.5 hours / session

Concepts Addressed

Fundamentals of compressible fluid dynamics and application to external and internal flows. Quasi-one-dimensional channel flow, extensions, and analysis of multi-dimensional flows in nozzles, diffusers, and inlets. Forces, moments, and loss generation resulting from compressible fluid flow interactions with aerodynamic shapes in subsonic, supersonic, transonic, and hypersonic flight, shock waves, and vortices. Disturbance behavior in unsteady compressible flow.

Learning Objectives

Students will be able to:

1. Describe assumptions, physical meaning of terms and to utilize key relationships for compressible flow, speed of sound, isentropic and non-isentropic flows, and potential and rotational flows;
2. Calculate the effect of area change, shaft work, heat addition, mass addition and friction on flow states in a compressible channel flow, including effects on mass flow capacity and flow regime;
3. Characterize quantitatively the behavior of velocity and density non-uniformities in an unsteady compressible flow including their evolution in fluid system components;
4. Estimate the lift and drag for basic aerodynamic shapes in compressible, inviscid flows.

Measurable Outcomes

Students will be able to:

1. Describe the assumptions and physical meaning of terms in the equations of motion for continuum flow;
2. Define quantitatively the regimes of applicability of quasi-one-dimensional channel flow theory;
3. Define quantitatively what it means for a flow to be considered “compressible”;
4. Define quantitatively effects of swirl and flow non-uniformity on maximum flow per unit area in a channel;
5. Explain the starting behavior of supersonic diffusers and inlets;
6. Characterize quantitatively the links between flow angle and pressure changes in a supersonic flow and the differences with subsonic flows;
7. Define the conditions for, and effect on flow state of the different types of discontinuities that occur in a compressible flow;
8. Describe expressions for and explain the link between vorticity generation and gradients in shock strength;
9. Use the Method of Characteristics to analyze a variety of internal and external flows: airfoils, inlets, nozzles, and jet flows;
10. Use the Method of Characteristics to design optimum inlets, nozzles, and wind tunnels;
11. Define the similarity principles that apply to compressible flows;
12. Calculate the lift and drag over simple aerodynamic shapes in compressible, inviscid flows.

Quizzes/Problem Sets

There are approximately six problem sets, an oral mid term exam, and an oral final exam.

Lecturers

Prof. Z. S. Spakovszky
Prof. W. L. Harris

Class Exercises

The lectures are held twice a week for 1.5 hours per session.