Aerodinmica Bsica Prof Dr Fernando Martini Catalano Aula

Aerodinâmica Básica • Prof. Dr Fernando Martini Catalano

Aula 1 Tópicos: 1. Fatos Históricos a) Sustentação e circulação condição de Kutta 2. Tipos de escoamentos a) Laminar a) Turbulento b) Camada Limite c) Número de Reynolds e Número de Mach d) Atmosfera padrão 3. Definições aeronáuticas a) Forças e momentos aerodinamicos b) Tipos de arrasto 4. Aerofolios a) Tipos de aerofólios e suas caracteristicas geométricas b) Distribuição de pressão i. Coeficiente de pressão ii. Efeito da geometria iii. High Lift Sections

1. Fatos Históricos Inventions reached their limit long ago, and I see no hope for further development. - Julius Frontinus, 1 st century A. D. Heavier-than-air flying machines are impossible - Physicist, Lord Kelvin, President, Royal Society, [ENGLAND] 1885. All attempts at artificial aviation are not only dangerous to life but doomed to failure from an engineering standpoint. — editor of 'The Times' of London, 1905 Airplanes are interesting toys but of no military value. — Marshal Ferdinand Foch, professor of strategy, Ecole Superiure de Guerre, 1911

1. Fatos Históricos The earliest serious work on the development of airfoil sections began in the late 1800's. Although it was known that flat plates would produce lift when set at an angle of incidence, some suspected that shapes with curvature, that more closely resembled bird wings would produce more lift or do so more efficiently. H. F. Phillips patented a series of airfoil shapes in 1884 after testing them in one of the earliest wind tunnels in which "artificial currents of air (were) produced from induction by a steam jet in a wooden trunk or conduit. " Octave Chanute writes in 1893, ". . . it seems very desirable that further scientific experiments be be made on concavo-convex surfaces of varying shapes, for it is not impossible that the difference between success and failure of a proposed flying machine will depend upon the sustaining effect between a plane surface and one properly curved to get a maximum of 'lift'. "

1. Fatos Históricos At nearly the same time Otto Lilienthal had similar ideas. After carefully measuring the shapes of bird wings, he tested the airfoils shown here (reproduced from his 1894 book, "Bird Flight as the Basis of Aviation") on a 7 m diameter "whirling machine". Lilienthal believed that the key to successful flight was wing curvature or camber. He also experimented with different nose radii and thickness distributions.

a) Sustentação e circulação condição de Kutta Starting vortex

The Kutta Condition

1. Tipos de escoamentos: a) Laminar b) Turbulento

a) Número de Reynolds Note that multiplying the Reynolds number , by yields which is the ratio,

a) Número de Reynolds Laminar Transitional Turbulent

a) Número de Reynolds

a) Camada Limite (Boundary Layer)

Número de Reynolds e Número de Mach Da equação de Reyleigh as forças aerodinamicas agindo numa familia de corpos geometricamente similares (isso inclui similaridade na direção do escoamento) : É o número de Reynolds onde: Número de Mach V/a

a) Tipos de aerofólios e suas caracteristicas geométricas

Definições aeronáuticas a) Forças e momentos aerodinamicos b) Tipos de arrasto c) Distribuição de pressão d) Estol e) Sistemas de alta sustentação

Lift coefficient Drag coefficient

Centro aerodinâmico : local onde Cm = cte independentemente de a Centro de pressão: local onde Cm=0 depende de a

Tipos de arrasto Arrasto de atrito Arrasto de pressão boundary layer presure drag or form drag Induced drag Wave drag Pressure drag + friction drag = profile drag

Friction drag

Drag Breakdown Cruize

Distribuição de pressão Coeficiente de pressão

Efeito do NRey

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