7,583 research outputs found
Lifting surface theory for a helicopter rotor in forward flight
A lifting surface theory was developed for a helicopter rotor in forward flight for compressible and incompressible flow. The method utilizes the concept of the linearized acceleration potential and makes use of the vortex lattice procedure. Calculations demonstrating the application of the method are given in terms of the lift distribution on a single rotor, a two-bladed rotor, and a rotor with swept-forward and swept-back tips. In addition, the lift on a rotor which is vibrating in a pitching mode at 4/rev is given. Compressibility effects and interference effects for a two-bladed rotor are discussed
Lifting surface theory for a helicopter rotor in forward flight
A lifting surface theory has been developed for a helicopter rotor in forward flight for incompressible flow. The method utilized the concept of the linearized acceleration potential and make use of the vortex lattice procedures. Results in terms of lift coefficient slope for several forward flight conditions are given
A study of longitudinal oscillations of propellant tanks and wave propagations in feed lines. Part I - One-dimensional wave propagation in a feed line
Longitudinal oscillations of propellant tanks and wave propagations in feed lines with streaming flui
A study of longitudianl oscillations of propellant tanks and wave propagations in feed lines. Part IV - Longitudinal oscillation of a propellant-filled flexible hemispherical tank
Longitudinal oscillation of propellant-filled flexible hemispherical tan
A study of longitudinal oscillations of propellant tanks and wave propagations in feed lines. Part II - Wave propagation in elastic pipe filled with incompressible viscous fluid
Fluid wave propagation in liquid propellant feed syste
Uniformization, Calogero-Moser/Heun duality and Sutherland/bubbling pants
Inspired by the work of Alday, Gaiotto and Tachikawa (AGT), we saw the
revival of Poincar{\'{e}}'s uniformization problem and Fuchsian equations
obtained thereof.
Three distinguished aspects are possessed by Fuchsian equations. First, they
are available via imposing a classical Liouville limit on level-two null-vector
conditions. Second, they fall into some A_1-type integrable systems. Third, the
stress-tensor present there (in terms of the Q-form) manifests itself as a kind
of one-dimensional "curve".
Thereby, a contact with the recently proposed Nekrasov-Shatashvili limit was
soon made on the one hand, whilst the seemingly mysterious derivation of
Seiberg-Witten prepotentials from integrable models become resolved on the
other hand. Moreover, AGT conjecture can just be regarded as a quantum version
of the previous Poincar{\'{e}}'s approach.
Equipped with these observations, we examined relations between spheric and
toric (classical) conformal blocks via Calogero-Moser/Heun duality. Besides, as
Sutherland model is also obtainable from Calogero-Moser by pinching tori at one
point, we tried to understand its eigenstates from the viewpoint of toric
diagrams with possibly many surface operators (toric branes) inserted. A
picture called "bubbling pants" then emerged and reproduced well-known results
of the non-critical self-dual c=1 string theory under a "blown-down" limit.Comment: 17 pages, 4 figures; v2: corrections and references added; v3:
Section 2.4.1 newly added thanks to JHEP referee advice. That classical
four-point spheric conformal blocks reproducing known SW prepotentials is
demonstrated via more examples, to appear in JHEP; v4: TexStyle changed onl
Casimir Forces and Graphene Sheets
The Casimir force between two infinitely thin parallel sheets in a setting of
such sheets is found. The finite two-dimensional conductivities, which
describe the dispersive and absorptive properties of each sheet, are taken into
account, whereupon the theory is applied to interacting graphenes. By exploring
similarities with in-plane optical spectra for graphite, the conductivity of
graphene is modeled as a combination of Lorentz type oscillators. We find that
the graphene transparency and the existence of a universal constant
conductivity result in graphene/graphene Casimir interaction at
large separations to have the same distance dependence as the one for perfect
conductors but with much smaller magnitude
Health status of older adults with Type 2 diabetes mellitus after aerobic or resistance training: A randomised trial
10.1186/1477-7525-9-59Health and Quality of Life Outcomes9
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