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Determining Thrust Effects of Obstruction Behind Propeller

Question asked by Collin Huston on Apr 22, 2012

Hoping to gain some help from the Flow community here. Currently a university student (undergrad), working on a final lab project. We are hopping to measure the effects on net thrust when an obstruction is placed behind a propeller. The lab setup is a 24in propeller mounted to a force balance to measure thrust, the propeller is controlled for a constant RPM. Behind the propeller (~10mm) is a flat circular disc to simulate a motor attachment or other flow obstruction. The size of this disc will be varied to determine a thrust to area realtionship.

The part of the that I am hoping for some assitance with is obtaining theorhetical results. Current knowledge leaves hand analysis to not much more than a uniform flow over a bluff body which would neglect a large number of the interesting interactions this blockage would cause. It was suggested by our professor that we use the Flow Simulation package but I haven't found anybody here that can assist with that.

I've been playing around with this a bit and am looking for some advice as for how to proceed.


Internal flow (large pipe over system) with a fan boundary condition.

External flow with constant velocity flow over obstruction

Extranal flow with propellor and a rotational frame aound this to provide the flow.


Option three seems to be best to me but I am not sure what I want to be using in the goals to get the thurst produced.

I know there is a lot here but I appreciate any and all help with this.