Comodo Trusted Site Seal
SSL Certificate

SBA Invent Logo

Fluid Mechanics: Boundary Layer

As fluid flows over a submerged object a boundary layer is formed. The boundary layer is due to the shear stress caused by the viscous effects of the fluid as it moves over the object. Depending on the length of the object and the speed of the fluid, the boundary layer could exhibit both laminar and turbulent flow. Refer to the figure below.

Boundary Layer across a flat plate

To determine if the fluid has a laminar or turbulent flow as it moves over the object Reynolds number would be used. Depending upon the surface roughness, the transition from laminar flow to turbulent flow occurs at a Reynolds number of 2X105 to 3X106. To calculate the Reynolds number for fluid flow over a flat plate the following equation would be used.

Reynolds number equation for a flat plate (1)

In addition to determining if the flow is laminar or turbulent Reynolds number also determines the importance of the viscous effects. As Reynolds number becomes larger the viscous effects aren't as important at the front of the boundary layer, but become much more important as you near the end of the boundary layer. Also, the larger the Reynolds number the thinner the boundary layer becomes.

Feedback and Recommendations





Recommended Text Books








We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

| © Copyright 2011 - 2018 | Prepared by S. B. Amirault, Founder of S.B.A. Invent | Terms & Conditions | Privacy |

Site Update

S.B.A. Invent has just implemented a new Forums. If you have questions, or feel like you can answer other people's questions, go check it out.

S.B.A. Invent Forums