Propeller Guard Information Center

Archive for CFD

Jan
29
2012

Propeller Guard CFD: Oliver Lee Thesis

by Gary

Propeller Guard Design: An Investigation Using CFD. Oliver Lee. University of Sydney (Australia). November 2011.

Mercury CFD mesh

Mercury Marine CFD mesh

We are thrilled to welcome this Computational Fluid Dynamics (CFD) analysis of propeller guards into the library of academic research studies on propeller guards by college students around the world. We also proud to have been a small part of it as it developed. A huge thanks to Oliver Lee for his efforts, to Dr. Steve Armfield his supervisor, to Julian Todd (an Australian propeller safety advocate who assisted with the project), and to the University of Sydney for all their support.

We first heard from Oliver Lee back in late March 2011 as he was getting underway on his Senior Thesis and were able to point him to some information and other studies he found helpful.

Since then he took on a broad swath of propeller guard topics in addition to performing the CFD analysis:

  • Surveyed the types of propeller guards and other propeller safety devices available
  • Investigated the history of propeller guards and the debate surrounding their use
  • Investigated the accident frequency of propeller guards
  • Investigated the relative costs of propeller guard designs
  • Investigated the Australian Safety Propeller and how it fits within this arena
  • Developed a propeller guard rating system based on the protection provided
  • Developed the model and the equations for the CFD analysis

You can download the full pdf document from the link below the thesis. Read More→

0 Categories : Research Projects
Jul
16
2011

Hydrodynamics of Propeller Accidents Part 2 – Right Whale Collision Research

by Gary

Following up on Hydrodynamics of Propeller Accidents Part 1, we now share some research work that looks very applicable to future hydrodynamic studies of human body / swimmer / man overboard interactions with boats, drives, propellers, and propeller guards.

Whale Model

Whale Model

We recently came across some hydrodynamic studies of whale interactions with ships, ship hulls, and ship propellers. One study was done at Carderock (the U.S. Navy lab facility we earlier suggested as a possible location to do full scale interaction studies with small boats). In the whale ship interaction study, they used a scale model of a huge containership with an elliptical bow bulb along with an instrumented model of a right whale.

The study is cited below.

Hydrodynamics of a Ship/Whale Collision.
Gregory K. Silber, Jonathan Slutsky, and Shannon Bettridge.
Journal of Experimental Marine Biology and Ecology.
Vol.391 (2010) Pages 10-19.
an Elsevier Journal.

Several quotes in the journal are strikingly similar to the needs of propeller guard hydrodynamic studies. The abstract contained the quote below:

“Factors influencing the incidence and severity of ship strikes are not well understood, although vessel speed appears to be a strong contributor. The purpose of this study was to characterize the hydrodynamic effects near a moving hull that may cause a whale to be drawn in or repelled from the hull, and to assess the acceleration exerted on a whale at the time of impact.”

Read More→

0 Categories : Our Thoughts on Propeller Safety Topics
Jul
15
2011

Hydrodynamics of Propeller Accidents – Part 1 the History

by Gary

Little research has been done surrounding the hydromechanics of people / swimmers/ man overboard encounters with propellers or propeller guards. We will now explore this field, some of the opportunities it presents, and some recent research that looks very applicable to studying the hydrodynamics of human / boat / propeller / propeller guard interactions. We will begin by exploring the history of what has been done to date. Read More→

0 Categories : Our Thoughts on Propeller Safety Topics
Jun
28
2011

Computational Fluid Dynamics (CFD) in Modeling & Testing of Propeller Guards

by Gary

We have been promoting the use of Computational Fluid Dynamics (CFD) in the development of prop guards for a long time. It’s been on our Help Us page for several years, we mentioned CFD in our January 2009 post on a Propeller Guard With Reduced Drag, and just a few days ago we briefly discussed the use of CFD in our The Emperor Has No Boat: SUNY Propeller Guard Testing post. In addition, our efforts to encourage engineering and design students working on student projects, thesis, and dissertations to consider studying propeller guards has a student that looks like he is going to be working at least in part, on propeller guard CFD.

Computational Fluid Dynamics (CFD) is a natural fit for propeller guard design. It allows sorting through the design variables to optimize the propeller guards to reduce drag, minimize their impact on boat handling issues, make sure cavitation issues do not cause a problem, and even test the interaction between propeller guards and humans (human factors issues of being struck by a guard, being entrapped, or being pulled into a recreational boat propeller). Read More→

0 Categories : Our Thoughts on Propeller Safety Topics

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