Jelena Svorcan

TWO-DIMENSIONAL NUMERICAL ANALYSIS OF ACTIVE FLOW CONTROL BY STEADY BLOWING ALONG FOIL SUCTION SIDE BY DIFFERENT URANS TURBULENCE MODELS

The effects of active separation control by steady blowing jets were investigated numerically on three different examples: subsonic flow past Aerospatiale A air- foil at 13o angle-of-attack, transonic flow past NACA 0012 airfoil at 4o angle-of- attack, and transonic flow in linear compressor/turbine cascade. Performed analyses are two-dimensional, flow is turbulent (or transitional) while fluid is viscous and compressible. Jets are positioned along the suction sides of the foils, the first one being located just upstream of the separation point, and modeled by source terms added to flow equations. Several different jet diameters and intensities are investigated. As the choice of turbulence model affects the final solution of Reynolds equations, turbulence is modeled by four different models: Spalart- Allmaras, realizable k-e, k-ω SST, and γ-Reθ, and a comparison of obtained results is performed. Goals of the study include definition of an adequate numerical setting that enables sufficiently correct simulation of the problems in question as well as evaluation of the possible increase in aerodynamic performances. Lift coefficients, lift-to-drag ratios or relative pressure differences are improved for all controlled cases.

Manufacturing Technology of Aircraft and Wind Turbine Blades Models, Plugs and Moulds

Rapid prototyping/manufacturing technology, as one of the fastest growing technologies, made its way into aeronautical industry long time ago. Beside huge cost and time savings, its main advantage lies in designers’ freedom to create new and innovative parts and systems. Today, there are many different rapid prototyping technologies available. This paper presents one possible manufacturing technology for producing accurate parts directly from computer-aided-design (CAD) models using 3-axis numerically controlled machine (in the form of subtractive milling). This process allows optimization of the design since changes can be easily incorporated into the three-dimensional (3D) model. Technology is applied on small aircraft and wind turbine blade models, and also on wind turbine blade mould, which can be used for both experimental and teaching purposes. Main advantages of the presented processes include: standardization, increased quality and accuracy, repeatability, cost and time reduction.

Computational analysis of helicopter main rotor blades in ground effect

Numerical investigation of an isolated representative helicopter main rotor has been performed in ANSYS FLUENT 16.2. In general, flow field around the rotor is unsteady, three-dimensional, complex and vortical. Such a simulation requires substantial computational resources. Ground effect, which improves the aerodynamic performances of the rotor, represents an additional challenge to numerical modeling. In this study, flow field is computed by Unsteady Reynolds Averaged NavierStokes (URANS) equations. Both Frame of reference and Sliding mesh approaches were employed to model the rotor rotation. Obtained results are compared to results obtained by simpler, sufficiently reliable models such as Momentum Theory (MT) and Blade Element Momentum Theory (BEMT). Presented results include fluid flow visualizations in the form of pressure, velocity and vorticity contours and the values of aerodynamic coefficients.