Model investigations of the aerodynamic coefficients of iced cables in cable-stayed bridges

Piotr Górski,

Marcin Tatara,

Stanislav Pospíšil,

Sergey Kuznetsov

Abstrakt

This paper presents the wind tunnel investigations of the mean aerodynamic coefficients of the stationary iced model in cable-stayed bridges. The investigations were performed in a Climatic Wind Tunnel Laboratory at the Czech Academy of Sciences in Telč. The icing of the inclined cable model was made experimentally. The shape of the iced model was mapped by a photogrammetry method. The new iced cable model was made by using a 3D printer. The aerodynamic drag, lift and moment coefficients were determined with respect to three principal angles of wind attack within the range of the Reynolds number between 2.5·104 and 13.6·104 at a turbulence intensity of 5 %. It was found that the drag coefficient values of the iced cable model are higher than for a circular smooth cylinder. The obtained results could constitute a basis to formulate a mathematical description of the wind load acting on the iced cables of cable-supported bridges.

Keywords: bridge cable, ice accretion, angle of wind attack, aerodynamic coefficient

Streszczenie
W pracy podano sposób i wyniki badań statycznych współczynników aerodynamicznych nieruchomego modelu oblodzonego cięgna mostu podwieszonego. Badania wykonano w tunelu aerodynamicznym Laboratorium Czeskiej Akademii Nauk w Telč. Zrealizowano doświadczalne oblodzenie nachylonego modelu cięgna. Otrzymane oblodzenie zarejestrowano metodą fotogrametrii. Wykonano nowy model oblodzonego cięgna metodą druku 3D. Współczynniki aerodynamiczne wyznaczono przy trzech podstawowych kierunkach napływającego powietrza w zakresie liczby Reynoldsa od 2,5·104 do 13,6·104 i przy średniej intensywności turbulencji powietrza 5%. Stwierdzono, że wartości współczynnika oporu aerodynamicznego modelu oblodzonego cięgna są większe w porównaniu do wartości otrzymanych dla cylindra. Otrzymane wyniki mogą stanowić podstawę do sformułowania matematycznego opisu modelu obciążenia wiatrem oblodzonych cięgien mostowych.

Słowa kluczowe: cięgna mostowe, oblodzenie, kąt napływu powietrza, współczynnik aerodynamiczny
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