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

Lecture

Schlieren / BOS Visualisation

In course

ME-343: Compressible-fluid dynamics

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

Description

This lecture explores the Background-Oriented Schlieren (BOS) technique, which uses environmental patterns instead of mirrors to visualize shock waves and compressible flow phenomena. The instructor showcases how BOS has been applied to study phenomena such as shock waves from explosions, compressible flow around helicopter blades, and interactions between supersonic aircraft. The lecture also discusses the use of natural elements like clouds and the sun to visualize shock waves in the sky, showcasing innovative applications of the BOS technique in aerodynamics.

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 (27)

Scientific visualization

Scientific visualization (also spelled scientific visualisation) is an interdisciplinary branch of science concerned with the visualization of scientific phenomena. It is also considered a subset of computer graphics, a branch of computer science. The purpose of scientific visualization is to graphically illustrate scientific data to enable scientists to understand, illustrate, and glean insight from their data.

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.

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.

Supersonic transport

A supersonic transport (SST) or a supersonic airliner is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. To date, the only SSTs to see regular service have been Concorde and the Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 and it was last flown in 1999 by NASA. Concorde's last commercial flight was in October 2003, with a November 26, 2003 ferry flight being its last airborne operation.

Incompressible flow

In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric flow) refers to a flow in which the material density is constant within a fluid parcel—an infinitesimal volume that moves with the flow velocity. An equivalent statement that implies incompressibility is that the divergence of the flow velocity is zero (see the derivation below, which illustrates why these conditions are equivalent). Incompressible flow does not imply that the fluid itself is incompressible.

Related lectures (35)

2D Potential Flows

Explores 2D potential flows in fluid dynamics, focusing on stream function and velocity potential relationships and visualization techniques.

Supersonic Wind Tunnel - EPFL Rocket Team

Presents a project to visualize supersonic flows for rocket design.

Inviscid Flows: Understanding Fluid Dynamics

Explores inviscid flows, Reynolds number importance, linear deformations, and volume change in fluid dynamics.

Momentum Equation

Explores the application of the momentum equation in fluid flow analysis, emphasizing force calculations on structures and practical examples.

Thermodynamics: Fluid Statics