Question

5) The following about turbulent flow in a pipe is true, EXCEPT a) The pipe cross-sectional average velocity is half of the centerline velocity (i.e. V = 0.5V.) b) The flow Reynolds number is beyond 4100 c) The flow consists of a viscous sublayer, a buffle layer (viscous and turbulent effect both important) and a fully turbulent region up to pipe centerline d) Reynolds-averaged (time mean) velocity is used to describe flow velocity 6) The boundary layer (BL) theory does not apply when the following happens, EXCEPT, a. the Reynolds number based on the linear dimension is very small b. there is a boundary layer separation happening it applies in a turbulent boundary layer on a flat plat d. the linear dimension of an object in the flow direction is very, very small c.

Answer 1

5 E for a turbulent flow in a pipe, all given option are correct Except @ The pipe cross-sectional average velocity is half q the centreline velocity.cie T= 0.5 ve) Explanation . j = 0.5 ve @ 0.5 Xmax It holds true for Laminar flow only & The boundary layer (B1) theory does not apply when the following , EXCEPT @ The Reynold number based on the linear dimension is very small, Explanation. In boundary layer segich viscous force dominates Inertia form & Reynold number : Inertia force viscous forcef / tinta