Update: 06/10/2005

Flow Analysis and Visualization

There are many unresolved problems in flow analysis left: What are vortices, how do they roll up and dissipate? What is turbulence and what is its influence on technical flows? When taking into account that for instance a 10% decreased fuel consumption of a commercial aircraft can double the profit, it seems to be very important to get a better understanding of those aerodynamic influences. Therefore the development of novel theoretical simulation models and experimental visualization and measurement techniques is one of the main activities at the F.I.B.U.S. research institute.
A new flow visualization method, the " Flow Visualization Gun", has been developed and applied to different flow problems like vortex behaviour at helicopter rotors, wind induced waves on water surfaces, or air condition flow types. Theoretical models of integral type (Biot- Savart, Vortex-Lattice) have been developed for helicopter rotor flow and wind turbine flow.

Flow Experiments

Supersonic Turbine Rotor Flow

Visualized by 4 Color Schlieren Technique

Helicopter Rotor Flow

Tip Vortex Interaction with Rotorblade,

Visualized by Titanium Smoke, Color Enhanced by Imagev Analysis

download Quicktime Movie 100 Kb

download MPEG Movie 17 kB

Helicopter Forward Flight

Tip Vortex Path, visualized by Smoke Blown out of the Blade Tips.

Slow Forward Flight: Advance Ratio is... = 0.1

download MPEG Movie 53 kB

Helicopter Forward Flight

Tip Vortex Path, visualized by Smoke Blown out of the Blade Tips.

Faster Forward Flight: Advance Ratio is... = 0.2

download MPEG Movie 980 kB

Observation of vortex pairing and merging at hover with anhedral tip shape

Path of a spiraling double tip vortex, visualized by theatre smoke injected into the flow. The video clip is half a rotor turn, so set your mpeg-viewer to "repeat" and see the rotor turn forever...

In case of problems with your player please load the VMPEG player below!

More information in: "Special Vortices at a Helicopter Rotor Blade", AHS journal vol 35, no 4, Oct. 1990

download MPEG Movie 840 kB

Observation of vortex pairing due to asymmetrical vortex spacing

Path of the tip vortices using different tip shape on the two blades of the rotor, one blade anhedral, the other blade dihedral. Due to the different spacing a vortex pairing and spiraling can be observed which is almost independent from instabilities by recirculation or other disturbances. It is half a rotor turn only, so there is a jump from one tip shape to the other in the video clip.... :-(

In case of problems with your player please load the VMPEG player below!

Load here your VMPEG Player (and other players): MPEG.ORG
Load here your QuickTime Player for Mac, PC or UNIX


Flow Calculations

Calculated flow field of two bladed helicopter rotor, using free wake analysis method
Roll-up of vortex filaments im the trailing vortex sheet of the rotor blade, using a vortex lattice technique


Sorry, our computers are still busy finishing the flow calculations ;-)


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