Solidity is defined as the blade’s chord length divided by the distance between adjacent blades mounted on the cable.
BLADE TO WIND SPEED RATIO (BSR)
This is similar but not the same as Tip Speed Ratio (TSR), used for propeller turbines. BSR is the ratio defining how much faster the entire blade is moving compared to the wind speed.
SOLIDITY VS BSR
Solidity and BSR follow an inverse hyperbolic relationship. The lower the solidity, the higher the BSR and visa versa. High solidity limits the speed at which blades can travel because the following blade runs into the turbulence of the preceding blade, thereby limiting it’s speed.
FACTORS AFFECTING POWER PRODUCTION
The power produced by an airfoil is proportional to air density, blade area and air velocity squared.
Power in the wind = 0.5 x density x swept area x velocity3
Power Return from LWG Design
Power = Cp x 0.5 x density x swept area x velocity3 (where Cp is the power coefficient)