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The thrust, T, and torque, Q, depend on the propeller's diameter, D, revolutions, N, and rate of advance, , together with the character of the fluid in which the propeller is operating and gravity. These factors create the following non-dimensional relationship:
and the corresponding weighted solidity ratio is known as the thrust-weighted solidity ratio. [2] When rotor power or torque coefficient is assumed constant, the weighing function is: = and the corresponding weighted solidity ratio is known as the power or torque-weighted solidity ratio. This solidity ratio is analogous to the activity factor ...
The advance ratio is critical for determining the efficiency of a propeller. At different advance ratios, the propeller may produce more or less thrust. Engineers use this ratio to optimize the design of the propeller and the engine, ensuring that the vehicle operates efficiently at its intended cruising speed, see propeller theory.
The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. [3]
The wind imparts a torque on the wind turbine, thrust is a necessary by-product of torque. Newtonian physics dictates that for every action there is an equal and opposite reaction. If the wind imparts torque on the blades, then the blades must be imparting torque on the wind. This torque would then cause the flow to rotate.
The thrust and torque forces as computed by means of the theory are therefore greater for the elements near the tip than those found by experiment. [ 7 ] In order to eliminate scale effect , the wind tunnel tests on model wings should be run at the same value of Reynolds number (scale) as the corresponding elements in the propeller blades.
Specific impulse should not be confused with total thrust. Thrust is the force supplied by the engine and depends on the propellant mass flow through the engine. Specific impulse measures the thrust per propellant mass flow. Thrust and specific impulse are related by the design and propellants of the engine in question, but this relationship is ...
Traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction; when this is the case, traction is often expressed as the ratio of the maximum tractive force to the normal force and is termed the coefficient of traction (similar to coefficient of friction).