Turbulators

[indoorff]

Hi everyone,

I am working on some low reynolds number airfoils using Profili, and have found the performance can be theoretically increased if a turbulator is added. What I dont know, is the size and shape of the turbulator that profili adds for you. Does anyone know? If not, what sort of sizes tend to get used?

Chris

[Ollie]

http://www.aae.uiuc.edu/m-selig/uiuc_lsat/bookannouncement3.html
"Also, this volume contains a rather extensive study of the effect boundary-layer trips have on airfoil performance. Experience, however, has proven such a study to be impractical for every airfoil. Therefore, two candidate airfoils were selected which are representative of a majority of the airfoils used on R/C model aircraft. These were the SD7037 and the E374. Each was tested with various trip configurations (single, multiple), geometries (2-D, 3-D), locations, and heights."

http://www.soartech-aero.com/V2.htm
http://www.soartech-aero.com/V3.htm
http://www.aae.uiuc.edu/m-selig/uiuc_lsat/lsat_5bulletin.html
http://www.aae.uiuc.edu/m-selig/uiuc_lsat.html


http://www.engr.uiuc.edu/communications/engineering_research/1997/aero/AERODYNAMICS.html
Effects of Boundary Layer Trips on Laminar Separation Bubbles
M. S. Selig, C. A. Lyon
University of Illinois

This research focuses on the effects of surface roughness on transition in laminar separation bubbles appearing on airfoils at low Reynolds numbers. Extensive performance and flow visualization data will be taken on airfoils that exhibit laminar separation bubbles. These results will be compared with data taken on the same airfoils but with varying trip geometries and locations. Also, several representative trip geometries will be enlarged and subjected to similar flow conditions as those experienced on the airfoils. Detailed flowfield surveys will be performed to determine why some turbulators are more effective than others at promoting transition, thereby reducing the size of the drag-producing laminar bubbles.

[indoorff]

Thankyou very much. There is some good info there.

Chris

[durone]

Hi everyone,

I am working on some low reynolds number airfoils using Profili, and have found the performance can be theoretically increased if a turbulator is added. What I dont know, is the size and shape of the turbulator that profili adds for you. Does anyone know? If not, what sort of sizes tend to get used?

Chris

Profili-XFoil simulates a turbolator forcing the transiction of the stream in the specified point. See the XFoil documentation to know more about.
Then you must dimension in a right way the turbulator to obtain the transiction.
Some time ago I found in the web some formulas to do this, but now I cannot find them again...

ciao
Stefano

[arx_n_sparx]

The *easiest* way I know of to do this is to build and cover the wing. Add "trip strips" made of masking tape - they are easy to cut to whatever width you want and easy to reposition. Once you've decided where the optimum placement is replace the masking tape with pin striping tape from an automotive parts retailer .

Brad

[green66]

Turbulator placement / sizing (http://www.mh-aerotools.de/airfoils/turbulat.htm)