Analysis of induced drag in flow over rear wing of race car

Kod natjecateljskih automobila, u cilju ostvarivanja što veće sile na podlogu, pribjegava se posebnom oblikovanju podvozja automobila, te ugradnji prednjeg i stražnjeg krila. Željeno povećanje aerodinamičke sile ostvaruje se izvedbom krila s velikim specifičnim aerodinamičkim opterećenjem i to najčešće kao krila male vitkosti. U ovom radu su istražene strujne pojave pri opstrujavanju zadanog modela stražnjeg krila natjecateljskog automobila s posebnim osvrtom na inducirani otpor. Sama geometrija stražnjeg krila natjecateljskog automobila modelirana je u programskom paketu Solidworks i preuzeta od članova FSB Racing Teama. Dorade geometrije i proračunska domena izrađene su u programskom paketu Salome. Domena je ispunjena konačnim volumenima generiranim u programskom paketu cfMesh. Mrežom dominiraju pravilni heksaedarski volumeni, uz korištenje manjeg broja prijelaznih tetraedarskih ćelija te trokutnih prizmi kako bi se sačuvala geometrijska definicija rubova. Svi proračuni provedeni su s ulaznom neporemećenom brzinom od 30 m/s (108 km/h). Simulacije su napravljene uz pomoć programskog paketa OpenFoam, koristeći program za rješavanje modela stacionarnog strujanja uz k-omegaSST model turbulencije. Izrađeno je ukupno 5 simulacija uz promjenu geometrije stražnjeg krila. U analizi rezultata dan je prikaz raspodjele tlakova i brzina, te smanjenja koeficijenta otpora, odnosno povećanja koeficijenta uzgona.When it is about race cars, it is necessary to achive as more force to the base as it can. It is done by instalation of front and rear spoilers. Wanted enlargement of aerodynamic force is realized by using great loaded wing, most with low slenderness. In this work, stream phenomenon are analyzed with opposing rear wing of the race car. The special review is on the induced resistance. Geometry of the rear wing model has been designed in Solidworks program package and it is took over from students organisation FSB Racing team. Program package Salome is used for futher work on geometry and calculations. Domain grid is filled with finite volume generated in cfMesh program package. Mesh is structured by using hexahedron cells, with small number of transitional tetrahedral cells and triangular prisms used to preserve the surfaces of the geometry model. All calculations were performed with the same freestream velocity of 30 m/s (108 km/h). For all simulations a steady-state flow model with the k-omegaSST turbulence model was used as implemented in the OpenFOAM software library. There are totally 5 simulations with changing the geometry of rear wing. In results, distribution of pressure (increase in the coefficient of lift), speed and reduced coefficient of resistance are shown