Airfoil operating in reverse airflow
Airfoil operating in reverse airflow
(OP)
Does anyone know of any sources of information related to the, lift, drag, center of pressure etc. on airfoils when the airfoil is being subjected to reverse airflow. I.e. where the air stream is flowing from the [labeled] trailing edge to the [labeled] leading edge.
Thanks
Thanks





RE: Airfoil operating in reverse airflow
RE: Airfoil operating in reverse airflow
HI
The best source of that type of information is from wind turbine data. The likes of Wind Engineering journal
Here's a link to a paper covering three airfoil's
http
Duncan
RE: Airfoil operating in reverse airflow
RE: Airfoil operating in reverse airflow
http://www.sandia.gov/wind/topical.htm#VAWTARCHIVE
Steven Fahey, CET
RE: Airfoil operating in reverse airflow
It isn't used ~ yet.
This link is to work I am doing, in the hope of developing the concept for future rotorcraft use. http://www.UniCopter.com/B473.html
verymadmac and SparWeb,
Thanks for the references. Something to read over a coffee.
rb1957,
Very little (public) work has been done on this subject. However, I believe that if pure rotorcraft are to have a future and achieve faster forward velocities, they must utilize the reverse velocity airflow on the retreating side of slowly rotating rotors.
Dave
RE: Airfoil operating in reverse airflow
Have you noticed how much the drag jumps up when you do this? Have you converted this drag into horsepower?
Steven Fahey, CET
RE: Airfoil operating in reverse airflow
No the drag has not been looked into yet. I am trying to assimilate any pertinent information first. It has been mentioned that someone had done it for the NACA 0012 and thinner airfoils.
A couple of positive features are that the airspeed will be less on the retreating side and that the drag on the retreating side will contribute to the rotation of the rotor.
Dave