Study and Design a Spoiler to Understand Aerodynamics with Various Angle of Attack at Different speeds

In this scope of study, various type of spoiler is researched out of which a pedestal spoiler is chosen to design as it generates a very good downforce and also has good aesthetic appeal to it, spoiler is designed considering actual scaled dimensions. Analysis on the designed pedestal spoiler is carried out to get to know how much the downforce is generated and at the same time how much drag coefficient is produced. Also, angle of attack of the spoiler in various degrees (9, 6, 4, 3, 2, 0, -2, - 3, -4, -6, -9, -12, -15) is carried out to know downforce at various angle of attack with various velocity (10, 15, 20, 25, 30, 35, 40, 45, 50) inputs in meter per seconds. After carrying out more than 80 analysis, found that highest downforce generated by the spoiler’s angle of attack is at (-6) degree with a 400 N of downforce and also with low drag. Velocity magnitude contour plot of each angle is provided to understand the air flow around each angle of attack. To validate the results given by the simulation tool a mathematical/analytical calculation are carried out for four angles of attack with a good result and also graphs are plotted for each validation to figure out the variation in them. Observing the validation’s graphs and calculations the difference between computational results and mathematical/analytical results is less than 5% indicating a proper process carried out in simulation and approximately giving realistic values that can be given in a wind tunnel aerodynamic test. Keywords: Spoiler, Aerodynamics, CAD, CFD, Drag coefficient, Lift coefficient, angle of attack.

Wave and tidal current sorting of shelf sediments southwest of England (summary only)

The relative roles of waves and tidal currents in sediment transport processes on the continental shelf off Lands End, southwest of England, are discussed in the light of ( a ) sediment grain size and boundary layer measurements in tidal currents, ( b ) regional variation in sediment parameters in relation to peak tidal and wave-induced currents, and ( c ) photographic and television observations of bedforms. ( a ) The sediments in this temperate study area are mainly zoogenic sands. The size parameters have been determined by settling velocity in a specially developed sedimentation tower. The average median diameter of sediments from 144 stations is dm^ — 1.40^ (medium grade sand), with a standard deviation of 0.43^. The linear bottom current which will just move this range of particle size must attain a drag velocity ( U *) of 2.37 cm s - 1 . This value is exceeded, only slightly, by the maximum drag velocity of 2.6 cm s - 1 measured in a bottom tidal current in the area. Thus, tidal currents alone are just competent to move the sediments. This movement is intermittent and limited to certain states of the tide.

The measurement of sand storms

In earlier papers (Bagnold 1936, 1937 a ) a description was given of experiments made in a wind tunnel 1 ft. sq. in cross-section to examine the conditions of wind and ground surface governing the mass flow q of sand across open country. It was found that: ( a ) The sand movement over a loose sand surface profoundly modifies the vertical velocity distribution of the wind, and that Prandtl's expression for the velocity distribution over a roughly surface of immobile grains v = 5.75 V log 30 z / k (1) (where the drag velocity V = √( T/p ), z is the height of measurement above the surface, k is the height above the surface at which v is zero―a height of the order of 1/30 of the dimension of the surface irregularity, i. e . the grain diameter, T is the surface drag and p the air density)