LOCAL SCOUR EVALUATION AROUND NONSUBMERGED CURVED GROYNES

This study presents a laboratory experiments for evaluating the local scour depth around S-shape solid non- submerged groynes using different number of these groynes and also different distances between them as two countermeasures to reduce the scour. The study was conducted in non- curved laboratory flume where uniform cohesion-less sand of median size (d50) equal to (0.7 mm) was used as the bed material. The physical hydraulic model of the groynes was made of polystyrene foam with fixed dimensions to operate under steady subcritical flow and clear water conditions. The studied parameters in this study were the number of groynes changed three times (single, double, triple), the distances between them altered also three times (1L, 1.5 L, 2L) and finally the hydraulic conditions (depth and velocity of the mean flow) also changed four times for each parameter. A new empirical equation was derived where its coefficient of determination indicates good agreement between the predicted results and the observed ones experimentally.