Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

1D Flows: Mach Number in a Nozzle

In course

ME-343: Compressible-fluid dynamics

Fluides compressibles, vitesse sonique, ondes de choc, détente. ...

Description

This lecture covers the conservation of mass, energy, and momentum in 1D flows, focusing on the effects of section variation and the transition from subsonic to supersonic regimes in a nozzle. The instructor explains the isentropic flow and the relationships between Mach number and flow area.

This video is available exclusively on Mediaspace for a restricted audience. Please log in to MediaSpace to access it if you have the necessary permissions.

Watch on Mediaspace

Instructor

Flavio Noca

Official source

Related concepts (25)

Mach number

Mach number (M or Ma) (mɑːk; max) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Austrian physicist and philosopher Ernst Mach. where: is the local Mach number, u is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and c is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature.

Hypersonic speed

In aerodynamics, a hypersonic speed is one that exceeds five times the speed of sound, often stated as starting at speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since individual physical changes in the airflow (like molecular dissociation and ionization) occur at different speeds; these effects collectively become important around Mach 5-10.

Compressible flow

Compressible flow (or gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. While all flows are compressible, flows are usually treated as being incompressible when the Mach number (the ratio of the speed of the flow to the speed of sound) is smaller than 0.3 (since the density change due to velocity is about 5% in that case). The study of compressible flow is relevant to high-speed aircraft, jet engines, rocket motors, high-speed entry into a planetary atmosphere, gas pipelines, commercial applications such as abrasive blasting, and many other fields.

Aerodynamics

Aerodynamics (ἀήρ aero (air) + δυναμική (dynamics)) is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an important domain of study in aeronautics. The term aerodynamics is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air.

Supersonic aircraft

A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound (Mach 1). Supersonic aircraft were developed in the second half of the twentieth century. Supersonic aircraft have been used for research and military purposes, but only two supersonic aircraft, the Tupolev Tu-144 (first flown on December 31, 1968) and the Concorde (first flown on March 2, 1969), ever entered service for civil use as airliners. Fighter jets are the most common example of supersonic aircraft.

Related lectures (32)

Supersonic Wind Tunnel - EPFL Rocket Team

Presents a project to visualize supersonic flows for rocket design.

Control Volume Approach: Mass Conservation and Physical Laws

Explores the control volume approach, emphasizing mass conservation and key physical laws.

Fluid Dynamics: Differential Conservation Laws and Equations

Covers the differential approach to fluid dynamics, focusing on conservation laws and the Cauchy stress tensor.

Fluid Mechanics: Control Volume Approach

Introduces powerful tools for analyzing fluid mechanics problems, emphasizing mass conservation, Newton's second law, and the continuity equation.

Straight Shocks: Entropy Log in to Mediaspace to watch this video