B Construction of Vane Cut-out pattern

B Construction of a Vane Cut-out Pattern of an Orthogonal Vane Assembly 

The negative values of Ath means that the vanes overlap. 

The upper, curved section of the vane complicates the design somewhat but provides for a much smoother entrance flow transition (compared to a completely straight vane element). The height of the curved section was selected to be half the total vane height. The overall height of the vane depends 

We recall that this section of the vane is to be of the same height as the straight section (20.725 mm). Thus, om rectangular pattern shown in Figs. 15.B.1 and 15.B.2 has a total height of 41.45 mm. We also wish for the curved sections to extend 30° around the hub, so that the total angular extent of each complete blade element is 90° - - 30° or 120°. Thus, each complete vane element will overlap an adjacent element by 60°. 

With this, we are now in a position to create the cut-out pattern for each vane in plan view. The straight or bottom half of the cutout pattern is very similar to what engineers sometimes design and attach to tall smokestacks to reduce flow-induced vibration at high wind loadings. The 

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