Projects

Project Title: A study into Turbulent Flow Over Rough Surfaces using CFD

Project type: Academic Research

Abstract

Understanding the flow over rough surfaces is an important problem in fluids engineering. Here, we present studies on turbulent flow over various roughness types. The rough surfaces considered in this study were based on the k and d -type behaviour used to classify the different roughness types. Previous results demonstrated that drag reduction can only be achieved using d -type roughness arranged in the streamwise direction. This arrangement is also known as flow over riblets. Obtaining an exact solution for such a problem is very challenging, therefore the problem was solved computationally using the finite element method. The flow simulation cases considered for this study were; laminar, turbulent and fully turbulent. The domain is represented by a channel flow with one sided profield roughness. Simulations were carried out to study the k and d -type behaviour over transverse and streamwise roughness. We were able to identify and benchmark the k and d -type behaviour for the flow over a transverse surface. Some similarities between the transverse and the streamwise roughness were observed in terms of k and d-type behaviour, mainly the production of stable vortices between the roughness elements, but further research is required to fully identify and benchmark the k and d-type behaviour in the flow over streamwise roughness.

Publications:

  • A. Alhinai and A. Nowakowski (2012), Understanding the Drag Reduction Properties of the flow over k- and d-type rough surfaces, European Congress on Computational Methods and Applied Science and Engineering (ECCOMAS). Full Text
  • A. Alhinai (2016), An investigation of classifying the flow over rough surfaces into k-and d-type in turbulent channel flow (Doctoral thesis, University of Sheffield, Sheffield, UK), Retrieved from http://etheses.whiterose.ac.uk/11255/

 

Project Title: Aerodynamics of High Speed Watercrafts

Project Type: Industrial Research

Abstract

This paper presents a computational model to simulate the flow around a high speed watercraft operating at cruise conditions. The objective was to investigate the aerodynamic performance of the current design and assess the adequacy of Computational Fluid Dynamics (CFD) to conduct detailed design studies. The model developed was based on the physical conditions generally encountered in wind tunnel tests. The results show that the model is capable of capturing the general flow patterns with reasonable accuracy. However, accurate predictions of friction were not possible using this method. Nevertheless, the model proved to be useful in estimating the aerodynamic forces acting on the surface of the watercraft. In turn, specific design recommendations to improve the aerodynamic performance of the water craft could be made using CFD.

Publication

  • Alhinai, A. A. (2015) Estimating the Aerodynamic Performance of a High Speed Watercraft Using Computational Fluid Dynamics. In: USES 2015 – The University of Sheffield Engineering Symposium, (DOI:10.15445/02012015.33). Full Text

 

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