Development and implementation of an urban wind field database for aircraft flight simulation

Vortical Gusts: Experimental Generation and Interaction with Wing

“…Within the broader field of unsteady aerodynamics, a body of research has focused on the aerodynamic response of wings to natural and man-made gusts. These include the unsteady flows around large buildings [1], in the airwake of ships [2], or incidental interactions with the wakes of aircraft [3,4] or rotors [5], including wind turbines. There has also been considerable effort invested into the creation of analogs of those gusts for further research, as outlined in the following.…”

“…The novel mechanism allowed for measurement of the resumption of vortex shedding from the downstream airfoil, which was impossible with the pitching generator. Nomenclature C L = lift coefficient, lift/(dynamic pressure × wing area) c a = airfoil chord length, m c p = plate chord length, m h = plate heave distance, m Re c = Reynolds number with respect to airfoil's chord length S = heaving speed ratio, V heave ∕U T = heaving time ratio, t heave ∕t cp t = time, s t a = normalized plate acceleration time, t accel ∕t cp t accel = plate acceleration time, s t c = chordwise convective time across airfoil, s t cp = chordwise convective time across plate, s t heave = heaving time, s t p = normalized airfoil pitching time, t pitch ∕t c t pitch = generator pitching time, s U = freestream speed, m∕s u = velocity in x direction, m∕s V heave = plate heaving speed, m∕s v = velocity in y direction, m∕s x = streamwise coordinate, m x 0 = streamwise position computed from unwrapping process, m y = cross-stream coordinate with respect to tunnel midline, m y 0 = initial plate distance from midline, m y peak = cross-stream position of maximum displacement of heaving plate, m y plate = cross-stream position of heaving plate, m y upstream = cross-stream position of pitching gust generator, m z = spanwise coordinate, m α = angle of attack of test article, rad (unless otherwise noted) α 1 = initial angle of pitching gust generator, rad (unless otherwise noted) α 2 = final angle of pitching gust generator, rad (unless otherwise noted) α eff = effective angle of attack of heaving gust generator, rad (unless otherwise noted) α upstream = angle of attack of pitching gust generator, rad (unless otherwise noted) Γ v = circulation of shed vortex, m 2 ∕s Γ v;est;heave = estimated circulation of shed vortex from heaving generator, m 2 ∕s Γ v;est;pitch = estimated circulation of shed vortex from pitching generator, m 2 ∕s Γ 2 = vortex identification criterion Δx = streamwise distance between generator and test article, m τ a = normalized time, t∕t c ω z = vorticity measured in x-y plane, s −1…”

Simulation Tool for Testing and Validating UAV Autopilots in Wind Gust Environments

“…Parametrization of flow around simple building structures was investigated by Baskaran et al, 13 Lakehal et al 14 and Meroney et al 15 Flows around urban canyon geometries was also researched by Baik et al 16 and Oke. 17 Galway et al 18 proposed the use of wind field database containing wind data of smaller parameterized CFD simulations. The proposed technique allows the reconstruction of large urban environments by using the small common urban structures from the database.…”

Urban Wake Field Generation Using LES for Application to Quadrotor Flight

“…However, the size and weight of vehicles able to operate within an urban environment are susceptible to external environmental effects such turbulent wakes produced by urban structures. This external susceptibility of aircraft flight in urban environments is outlined in the previous work of Etele [12] and Galway et al [13][14][15], as well as other studies such as Orr et al [16], Kothari et al [17], and Semsch et al [18].…”

“…The previous work of Galway et al [13][14][15] has a database of wake fields using RANS CFD methods for testing the flight performance of a fixed wing Aerosonde UAV [15] and Yamaha R-50 rotor-craft [14]. Based on growing popularity and accessibility of LES methods, and its limited application to SUA such as quadrotors in urban environments, this work aims to determine if the additional computational cost of LES is justified in comparison to RANS.…”