The rotor is modeled as an infinitely thin disc, inducing a constant velocity along the axis of rotation. The basic state of a helicopter is hovering. This disc creates a flow around the rotor. Under certain mathematical premises of the fluid, there can be extracted a mathematical connection between power, radius of the rotor, torque and induced velocity. Friction is not included.
For a stationary open rotor with no outer duct, such as a helicopter in hover, the power required to produce a given thrust is:
Wikimedia Commons has media related to Actuator disk theory.
Referencesedit
^Rankine, W.J. Macquorn (6 April 1865). "On the Mechanical Principals of the Action of Propellers". Transactions of the Royal Institution of Naval Architects. 6: 13 – via Hathi Trust.
^Froude, Robert (12 April 1889). "On the Part Played in Propulsion by Differences in Fluid Pressure". Transactions of the Royal Institution of Naval Architects. 30: 390 – via Hathi Trust.
April 11, 2024
momentum, theory, fluid, dynamics, momentum, theory, disk, actuator, theory, theory, describing, mathematical, model, ideal, actuator, disk, such, propeller, helicopter, rotor, rankine, 1865, alfred, george, greenhill, 1888, robert, edmund, froude, 1889, actua. In fluid dynamics momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk such as a propeller or helicopter rotor by W J M Rankine 1865 1 Alfred George Greenhill 1888 and Robert Edmund Froude 1889 2 An actuator disk accelerating a fluid flow from right to leftThe rotor is modeled as an infinitely thin disc inducing a constant velocity along the axis of rotation The basic state of a helicopter is hovering This disc creates a flow around the rotor Under certain mathematical premises of the fluid there can be extracted a mathematical connection between power radius of the rotor torque and induced velocity Friction is not included For a stationary open rotor with no outer duct such as a helicopter in hover the power required to produce a given thrust is P T32rA displaystyle P sqrt frac T 3 2 rho A where T is the thrust r displaystyle rho is the density of air or other medium A is the area of the rotor disc P is powerA device which converts the translational energy of the fluid into rotational energy of the axis or vice versa is called a Rankine disk actuator The real life implementations of such devices include marine and aviation propellers windmills helicopter rotors centrifugal pumps wind turbines turbochargers and chemical agitators See also editBlade element theory Circulation fluid dynamics Disk loading Kutta Joukowski theorem nbsp Wikimedia Commons has media related to Actuator disk theory References edit Rankine W J Macquorn 6 April 1865 On the Mechanical Principals of the Action of Propellers Transactions of the Royal Institution of Naval Architects 6 13 via Hathi Trust Froude Robert 12 April 1889 On the Part Played in Propulsion by Differences in Fluid Pressure Transactions of the Royal Institution of Naval Architects 30 390 via Hathi Trust Retrieved from https en wikipedia org w index php title Momentum theory amp oldid 1205596877, wikipedia, wiki, book, books, library,