, ▁a ▁sk imming ▁flow ▁regime ▁can ▁occur ▁( Sh ah he yd ari ▁et ▁al . ▁ 2 0 1 5 ). ▁N appe ▁flow ▁has ▁po ckets ▁of ▁air ▁at ▁each ▁step ▁whereas ▁sk imming ▁flow ▁does ▁not . ▁The ▁on set ▁of ▁sk imming ▁flow ▁can ▁be ▁defined ▁as : ▁ ▁( dc )= 1 . 0 5 7 * h ▁- ▁ 0 . 4 6 5 * h 2 / l ▁ ▁Where : ▁ ▁h ▁= ▁step ▁height ▁( m ) ▁ ▁l ▁= ▁step ▁length ▁( m ) ▁( dc ) ons et ▁= ▁the ▁critical ▁depth ▁of ▁the ▁on set ▁of ▁sk imming ▁flow ▁( m ) ▁ ▁N appe ▁Flow ▁— ▁For ▁the ▁n appe ▁flow ▁regime , ▁a ▁partially ▁or ▁fully ▁developed ▁hyd ra ul ic ▁jump ▁occurs ▁as ▁a ▁result ▁of ▁the ▁j ets ▁created ▁between ▁each ▁step .< ▁Energy ▁D iss ip ation ▁ ▁Where : ▁ ▁H dam ▁= ▁dam ▁cr est ▁head ▁above ▁the ▁down stream ▁toe ▁( m ) ▁ ▁H 0 ▁= ▁free ▁surface ▁elev ation ▁above ▁the ▁sp ill way ▁cr est ▁( m ) ▁ ▁H max ▁= ▁total ▁head ▁( m ) ▁ ▁d c ▁= ▁critical ▁flow ▁depth ▁ ▁H ▁= ▁head ▁loss ▁( m ) ▁ ▁Sk imming ▁Flow ▁Reg ime ▁Under ▁a ▁sk imming ▁flow ▁regime , ▁water ▁flows ▁in ▁a ▁coh er ent ▁stream ▁down ▁the ▁step . ▁Water ▁sk ims ▁the ▁top ▁of ▁each ▁step ▁as ▁it ▁flows ▁down