Sharif Digital Repository

A series of unsteady low speed wind tunnel tests on a section of a 660 Kw wind turbine blade which is under construction were conducted to examine the effects of distributed surface contamination on its performance characteristics. Model was tested at three mean angles of attack, 5, 10 and 18 degrees at the fixed oscillation domain of 5 degrees. Results show that contamination decreases the maximum lift coefficient more than 40 percent. However Reynolds number and oscillation frequency increase, have a positive effect on the maximum lift coefficient in the contaminated model and it decreased the difference between maximum lift coefficient in the clean airfoil and the contaminated one  

A series of low speed wind tunnel tests on a section of a 660 Kw wind turbine blade which is under constructer were conducted to examine the effects of distributed surface contamination on its performance characteristics. At first model was tested in the clean condition and after that it was tested with tree different types of roughness. The data shows that this particular airfoil is very sensitive to the applied surface roughness. For the contaminated model the roughness, 0.5mm height was distributed over the entire upper surface of the airfoil such that the distribution pattern was denser in the vicinity of the leading edge and thinner in the trailing edge area. Statistical data show that... 

A series of unsteady low speed wind tunnel tests on a section of a 660 Kw wind turbine blade under construction were conducted to examine the effects of distributed surface contamination on its performance characteristics. Our data shows that the airfoil is very sensitive to the applied surface roughness. Results show that contamination decreases static maximum lift coefficient more than 40 percent. In the dynamic test this effect is the same and is about 38 percent. Contamination decreases the width of the dynamic diagrams loop such and leads to the smooth stall on the airfoil  

A series of low speed wind tunnel tests were conducted on a section of a 660 kW wind turbine blade to examine the effects of distributed surface contamination on its performance characteristics. The selected airfoil was tested with a clean surface, two types of zigzag roughness, strip tape roughness and distributed contamination roughness. The straight and zigzag leading edge roughness models simplify the contamination results in an early turbulence transition. In this study, surface contamination was simulated by applying 0.5 mm height roughness over the entire upper surface of the airfoil. The distribution density varied from the leading edge to the trailing edge of the model. Our data... 

Numerous experiments were conducted on the section of a 660 kw wind turbine blade in a subsonic wind tunnel. The selected airfoil was tested with a clean and distributed contamination roughness surface, with a high and low tunnel turbulence intensity. Surface contamination was simulated by applying 0.5 mm height roughness over the entire upper surface of the airfoil. The surface pressure distribution is measured under a steady and unsteady condition, at three Reynolds numbers; 0.43, 0.85, and 1.3 million, and over a range of angles of attack, AOA=7°-19°. Unsteady data were acquired by both pitch and plunge-type oscillation of the model about its quarter chord at a reduced frequency of 0.07.... 

Existing closed-form solutions of contaminant transport problems are limited by the mathematically convenient assumption of uniform flow. These solutions cannot be used to investigate contaminant transport in coastal aquifers where seawater intrusion induces a variable velocity field. An adaptation of the Fourier-Galerkin method is introduced to obtain semi-analytical solutions for contaminant transport in a confined coastal aquifer in which the saltwater wedge is in equilibrium with a freshwater discharge flow. Two scenarios dealing with contaminant leakage from the aquifer top surface and contaminant migration from a source at the landward boundary are considered. Robust implementation of...