On wake vortex response for all combinations of five classes of aircraft

2004 ◽  
Vol 108 (1084) ◽  
pp. 295-310 ◽  
Author(s):  
L. M. B. C. Campos ◽  
J. M. G. Marques
Keyword(s):  
Wake Vortex ◽  
Dimensionless Form ◽  
Bank Angle ◽  
Rolling Moment ◽  
Tip Vortices ◽  
Transport Aircraft ◽  
Roll Rate ◽  
Wing Tip ◽  
Special Case ◽  
Light Medium

Abstract The present paper concerns the response of a following airplane to a pair of wing tip vortices left by a leading aircraft, represented by the Hallock-Burnham model, including the effect of vorticity decay between the two aircraft. The effect of vorticity is evaluated in terms of the induced rolling moment and also the lift loss; these specify the roll acceleration and the downward acceleration, respectively. The corresponding two response equations can be put into the same dimensionless form, and integrated using exponential integrals. This specifies the roll rate and sink rate as a function of time; besides the latter, the bank angle and altitude loss, are also plotted, all also as a function of time, for all combinations of leading and following aircraft in five classes. These are the three ICAO weight categories of light, medium and heavy, plus two other cases, viz the special case of the Boeing 757, which requires larger separations distances, and the case of a future very large transport aircraft (VLTA) exceeding significantly the size of a Boeing 747.

On the compensation and damping of roll induced by wake vortices

2014 ◽  
Vol 118 (1207) ◽  
pp. 1039-1061 ◽  
Author(s):  
L. M. B. C. Campos ◽  
J. M. G. Marques
Keyword(s):  
Exact Analytical Solution ◽  
Wake Vortex ◽  
Rolling Motion ◽  
Damping Factor ◽  
Wake Effect ◽  
Bank Angle ◽  
Rolling Moment ◽  
Roll Rate ◽  
Control Response ◽  
Light Medium

Abstract The effect of the wake of a leading aircraft on a following aircraft is demonstrated by calculating the rolling motion consisting of three terms: (i) the free rolling motion due to initial bank angle and roll rate; (ii) the forced wake response due the rolling moment induced by the wake encounter; (iii) the forced control response due to aileron deflection to counter the wake vortex effects. It is shown that in the absence of control action, the roll rate of the following aircraft goes through a peak, and then decays, leading to a constant asymptotic bank angle; the latter is a measure of the magnitude of the wake effect, e.g. is larger for weaker damping. The exact analytical solution of the roll equation appears as a power series of a damping factor, whose coefficients are exponential integrals of time; it is shown that the first two terms give an accuracy better than 2%. The theory is used to simulate 15 combinations of wake vortex encounters between leading and following aircraft in the five ICAO/FAA weight categories: light, medium, heavy, special (B757) and very large (A380).

Near field dynamics of wing tip vortices

2001 ◽  
Author(s):  
Lavi Zuhal ◽  
Morteza Gharib
Keyword(s):  
Near Field ◽  
Tip Vortices ◽  
Wing Tip

Meandering of Wing-Tip Vortices Interacting with a Cold Jet in the Extended Wake

2008 ◽  
pp. 223-242
Author(s):  
Frank T. Zurheide ◽  
Matthias Meinke ◽  
Wolfgang Schröder
Keyword(s):  
Tip Vortices ◽  
Wing Tip

A Study of Water Surface Deformation Due to Tip Vortices Wing-in-Ground Effect

2007 ◽  
Vol 51 (02) ◽  
pp. 182-186
Author(s):  
Tracie J. Barber
Keyword(s):  
Water Surface ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Ground Effect ◽  
Aerodynamic Performance ◽  
The Body ◽  
Vehicle Design ◽  
Two Dimensional ◽  
Tip Vortices ◽  
Wing Tip

The accurate prediction of ground effect aerodynamics is an important aspect of wing-in-ground (WIG) effect vehicle design. When WIG vehicles operate over water, the deformation of the nonrigid surface beneath the body may affect the aerodynamic performance of the craft. The likely surface deformation has been considered from a theoretical and numerical position. Both two-dimensional and three-dimensional cases have been considered, and results show that any deformation occurring on the water surface is likely to be caused by the wing tip vortices rather than an increased pressure distribution beneath the wing.

Realisation and testing of novel fully articulated bird-inspired flapping wings for efficient and agile UAVs

2021 ◽  
pp. 1-35
Author(s):  
D. Kumar ◽  
T. Goyal ◽  
S. Kamle ◽  
P.M. Mohite ◽  
E.M. Lau
Keyword(s):  
Aerodynamic Performance ◽  
Image Correlation ◽  
Right Wing ◽  
Left Wing ◽  
Bank Angle ◽  
Rolling Moment ◽  
Wind Speeds ◽  
Optimal Values ◽  
The Right ◽  
Dic Technique

Abstract Large birds have evolved an effective wing anatomy and mechanics, enabling airborne mastery of manoeuvres and endurance. For these very reasons, they are difficult to replicate and study. The aim of the present work is to achieve active wing articulations to mimic natural bird flapping towards efficient and agile Unmanned Aerial Vehicles (UAVs). The proposed design, bio-mimicking the black-headed gull, Larus ridibundus, has three active and independent servo-controlled wing joints at the shoulder, elbow and wrist to achieve complex controls. The construction of the wing is realised through a polymeric skin and carbon fibre–epoxy composite spars and ribs. The wing movements (flapping, span reduction and twisting) envelopes of the full-scale robotic gull (Robogull) are examined using the Digital Image Correlation (DIC) technique and laser displacement sensing. Its aerodynamic performance was evaluated in a wind tunnel at various flapping parameters, wind speeds and angles of attack. It is observed that a flapping amplitude of 45 $^\circ$ is more favourable than 90 $^\circ$ for generating higher lift and thrust, while also depending on the presence of span reduction, twist and wind speed. The model performs better at a flying velocity of 4m/s as compared with 8m/s. Both lift and thrust are high at a higher flapping frequency of 2.5Hz. Combined variation of the flapping frequency and stroke ratio should be considered for better aerodynamic performance. The combination of a lower stroke ratio of 0.5 with a flapping frequency of 2.5Hz generates higher lift and thrust than other combinations. Span reduction and wing twist notably and independently enhance lift and thrust, respectively. An increase in the angle-of-attack increases lift but decreases thrust. The model can also generate a significant rolling moment when set at a bank angle of 20 $^\circ$ and operated with independently controlled flapping amplitudes for the wings (45 $^\circ$ for the left wing and 90 $^\circ$ for the right wing). Based on the optimal values for the flapping amplitude (45 $^\circ$ ), flapping frequency (2.5Hz) and flying velocity (4m/s), the Strouhal number (St) of the Robogull model is 0.24, lying in the optimal range ( $0.2 < \mathrm{St} < 0.4$ ) for natural flyers and swimmers.

CHARACTERISTICS OF SPRAY DEPOSITS RESULTING FROM AIRCRAFT APPLICATION OF OIL-CARRIER SPRAYS

1957 ◽  
Vol 37 (2) ◽  
pp. 85-96 ◽  
Author(s):  
J. J. Sexsmith ◽  
D. T. Anderson ◽  
G. C. Russell ◽  
W. W. Hopewell ◽  
H. Hurtig
Keyword(s):  
Petri Dish ◽  
Ground Level ◽  
Assessment Data ◽  
Tip Vortices ◽  
Spray Booth ◽  
Oil Mixtures ◽  
Small Plot ◽  
Aerial Sprays ◽  
Aircraft Application ◽  
Wing Tip

Assessments were made of the physical properties of spray deposits from upwind and crosswind, single and multiple flight applications of oil-carrier spray applied by a small aircraft equipped for commercial weed spraying. Volume deposits were determined colorimetrically on petri dish collections of the dyed spray. Droplet assessment data were obtained from photographic enlargement of printflex sampling cards.Three peaks of spray deposit were found, resulting from the propeller blast and the wing-tip vortices. A greater percentage of spray was recovered at ground level, and more variation in volume deposit and droplet size occurred across the effective spray swath, in the upwind flight than in the crosswind flight application. Information obtained from these tests will be used in the construction of a spray booth, designed to apply simulated aerial sprays on a practical small-plot basis, for determining the causes of injury to grain crops resulting from aerial application of herbicide-oil mixtures.

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