The Atlantis Project is a wing-based autonomous sailing vessel, based on a Prindle-19 catamaran, that has demonstrated line following under automatic control to an accuracy of better than 0.3meters. This work details both the design of the wing section and the configuration analysis for a free-rotating, aerodynamically actuated wingsail that is used as themain propulsion system. Based on numeri...

A = heaving amplitude, m Cl = lift coefficient c = wing chord, m Dbl = boundary-layer domain Dout = outer flow domain F = aerodynamic force, N f = flapping frequency, s−1 k = πfc∕U, reduced frequency k = unit vector normal to the freestream velocity L, L 0 = lift or sectional lift, N or N · m−1 La, L 0 a = lift or sectional lift associated with the fluid acceleration, N or N · m−1 Lvor, L 0 vor...

This paper studies several problems that may exist in the aerodynamic design of low Mach number general aircraft, and discusses characteristics pressure distribution some related airfoils while part is verified by a multi-point laminar airfoil case. Firstly, issues which such as relatively large zero-lift drag coefficient, high stall performance requirements, variation range Reynolds number, ar...

The behavior of bubbles traveling in the proximity a tilted wall is studied experimentally to understand fundamental sliding motion inside turbulent boundary layers along an inclined wall. qualitative visualization confirms contribution bubble buoyancy on for negative and positive inclinations channel. An opto-acoustic combined measurement technique adopted explore motion. Liquid velocity profi...

In the present study, vortex-induced vibrations in both In-Line and Cross-Flow directions of long flexible cylinders within a uniform flow are predicted by modified wake oscillator model. detail, Van der Pol's model with drag lift coefficients being modelled as random variables. The statistics force coefficient, i.e. mean value standard deviation, extracted from literature reporting experimenta...

Single-mode Ge₂₈Sb₁₂Se₆₀ strip waveguides, fabricated with thermal evaporation and lift-off, were demonstrated at 1.03 µm. The linear and nonlinear optical properties of these waveguides were shown to be similar to bulk samples, with differences attributed to small variations in composition of ~4 atomic % or less. From z-scan measurements at 1.03 µm using circularly polarized, ~200 fs pulses at...

In order to predict the structural responses under random wind loads to avoid catastrophe failures, structural dynamic analysis is necessary, which requires a reasonable description of wind loads on structures. Based on the equations of fluid mechanics, equations for aerodynamic forces for structures in motion and coefficients of drag, lift and pitching moment for static structures are derived ...

α angle of attack, rad Γ circulation, m2s−1 λ wake wavelength, m ρ∞ free-stream air density, kgm −3 τ panel tangential vector ω angular velocity, rad s−1 a non-dimensional distance between aerofoil mid-chord and centre of rotation A panel area, m b semi-chord, m ∆b panel span, m B wingspan, m c aerofoil chord, m ∆c panel chord, m C Theodorsen’s function, C(k) = F (k) + iG(k) Cd sectional drag c...

Several approaches for modelling the longitudinal aerodynamic coefficients of a fighter aircraft at high angles of attack, including the unsteady effects are presented. A traditional approach where the model of the coefficient arises in the form of the steady and unsteady effects, the unsteady effect being modelled by means of transfer functions. The second approach uses an internal variable de...