First, the reference density should be the air density ... If you enabled variable density, select the value of the density at the inlet to your domain.1 - If the forces on the blades are similar, you need to enter the reference are as the blade area*3 ... (3*Chord length * span)n2- Here you need to enter effective length ... I don't remember the formulan3 -Yes you can obtain them .. but the values you get will be based on the reference values you set. So, in this case I recommend you calculate the force, and calculate the coefficients outside of fluent.n4- No, forces are not dependent on the reference valuesn5- You need to set the direction of the lift and drag by these vectors. Let's say, in your case, the flow is going in the -ve Z direction. Then, the vector will be (0,0,-1) and so onn