Ahmed Al Makky
Welcome to my ePortfolio.
I am a PhD student at the centre for Scientific Computing / School of Engineering at Warwick University. My research focus is on turbulent vortex rings. I run numerical simulations in order to look closely at turbulent vortex ring structures that occur in the flow. I have a BSc in Mechanical Engineering and an MSc in Sustainable Energy and Environment. I am also interested in teaching.
Project finish date is 26 November 2012.
I have tried to make my ePortfolio as useful as possible for the visitor.Please feel free to contact me regarding any questions in the field of computational fluid dynamics (CFD).
This website will still be updated till my university regestration ends therefore for researchers who are intrested to follow up my latest research updates they are advise to go to the following link:
About My Research:
What best describes my research vortex rings is the bubble rings blown by dolphins as can be seen in the following link:
After seeing the previous videos, this first question that comes in mind, whats the use of studying such a phenomena? The vortex ring phenomena has lots of applications, it is generated by giving a stationary mass of air a high amount of momentum at a short period of time, this happens in engines, in pumps, in combustion chambers ......etc. WIth this kind of action , if the researcher can capture this pattern using high frame rate capture cameras a through understanding of fluid mass transfer dynamics can be achieved. At first when the mass of gas is given its initial blow it stays intact , with the progress of time it starts fluctuating with the ring getting lots of curvature patterns on its surface until it gets to the point of break down. Depending on application comes the stage of concern for the researcher.
Coding Tutorials for Computational Fluid Dynamics:
New Simulation Runs Pictures:
Spray modelling, this is a test trial of water spraying using a novel spray design. Here is the latest tutorial for spray modelling enjoy Spray_modelling .
The required geometry for the spray tutorial is .
Running a simulation on a space shuttle model during the stage of re-entry.
Modelling the encountered wall shear stress during re-entry.
Modelling air flow around a Mig-15 model. Stream lines are used to see how smooth is the flow over the planes surface.
The next picture is used to see the velocity field from the point of inlet to the engine intakes.
Formual BMW F1 Trial:
Unfortunately i couldn’t get a finer mesh which lead to having the irregular mesh visible, the limitation was a license and hardware issue.
A prespective View:
Computer Modeling has been a fascination for me since 2004, starting with AutoCad working with it for several years, then worked with a software called Mechanical desktop for a period of time, during that period Mechanical desktop had a finite element analysis package with it but its set back was that it couldn’t handle complex geometries. The first time I used Solidworks was in summer 2005 which was for a short while, during that time I used it to create a library of parts for a piping project, at that time I felt that this software has the tools that i have been looking for. January 2005 I started working with Autodesk 3dmax this span for several years .Finally in 2008 thanks to Warwick university I got the chance to work with SolidWorks. During this period i got the chance to build my skills with this software, and got lots of assistance and help from collages especially Peter Kimber which has been of great support and help. What I can say that it’s user friendly to work with and I can see that its developing rapidly and has a bright future ahead.
Using ANSYS i got the chance to run simulations on the previously shown model and got the pressure distribution on the aircraft surface, the pressure contours show the regions of high pressure coloured red on the the nose section, leading wing edges and engine intakes .
Locating the lift force acting on the aircraft wings of an aircraft as shown:
Vorticies distribution for a starship model shown in blue color, while presure distribution on the plane surface is in yellow.
Solidworks provides the user with sketching and modeling tools engineers never would dream of. Projects that took months and years to implement now take much lesser time to do so. Not forgetting that it helps to find problems at an early stage once you start putting assemblies together and lessens the man recourses required to work on the project. Seeing how Mechanisms retract and their limitations helps the project. Because all the preparation work is conducted in virtual world.
Software Tutorials for Undergraduates and Graduates:
While working in industry you will be assigned problems to overcome, after completing your modeling stage and getting the product to do its main purpose , the next step is to validate that its shape and its parts work at their best, what is meant by that is dose the shape of the product produce more drag for the user such as a bikers helmet, or for adding car mirrors that have the least drag for the car design. The other issue for internal flows of a product such as ventilation air currents in a gear box or an electrical motor for a pump and the list will just go on and on. This is where star CCM comes is the need to model flows inside or outside a product so that it performs its best performance at the least price. The researcher has to import the model into star CCM and then see what flow patterns are formed due to different input parameters. Then comes the analysis part after the simulation is run due to lots of data is generated
The required file needed for the tutorial:
a-Assigning the faces of inflow,outflow and wall boundaries are the main focus of this tutorial.
b-The chose of turbulence model , steady or an unsteady case,type of fluid ....etc.
c-Making cross section planes for the data anaylsis part of the project.
d-How to run a simulation.
2-ANSYS CFX Tutorials:
ANSYS is a great software to work with , its provided at the school of engineering labs, i wish that you enjoy these tutorials.
A- Tutorial 1:
The required file needed for the tutorial:
The required file needed for the tutorial:
Ready Meshes that can be used for a CFD simulation:
The provided meshes are in Parasolid.x_t format, can be read striaght away into ANSYS or STAR-CCM+.The provided meshes are modeled for the purpose of providing the student with ready material to read into a CFD software, to run flow simulations and validate the generated flow pattern at later stages.
Internal Flows Meshes:
1-Flow Swirl Tube.
2- Separation Duct fitting.
3-Coal Swirl Combustor.
External Flows Meshes:
The mesh works and the output for a static turbine with none rotating turbines is shown below.
The figure bellow shows the flow pattern inside the heatexchanger, where the first set of three tubes get a high portion of the heat which they have to extract (10 deg), then comes the next set of three which have to extract 6 deg, then the next set of three 4deg and finally the last set of three will extract 2deg. Having a look at the simulation flow pattern proposes some design modifications that will be illustrated in further simulations. It is obvious from the bottom figure that the convective heat transfer is dominant on the first half of the heat exchanger.
2-Gas Turbine Combustion Chamber.
The mesh has been tested on several simulations ,at later stages a finner grid is the objective.
The figure below shows the velocity component in the z directions which is the z direction in our studied case
4-Engine Exhaust Nozzle.
5-Car Engine Combustion Chamber
1-Central Fugal Compressor.
Initially i had difficulty in getting the required mesh smoothnes usuing the Tetrahedral meshing ,got around the problem using Hexahedral Meshing, this is a top view of a centralfugal compressor, the simulation was run without applying a rotation to the compressor disc as an initial step to get an output of a vector field.
What is obvious is that compressor disc gives a uniform distribution of mass and velocity to the seven stages ( each stage is made up of a big and a small vane), which in some way required in gas turbines, as we can see we have seven high velocity points (illustrated by red arrows) which can reffer to the input of seven combustion chambers, this kind of compressor was first used on early models of jet engines.
3-Jet Engine Intake.
4-High Pressure Turbine.
This simulation was run to test the LES Dynamic model provided with ANSYS.
5-2D Rotor Stator Turbine Section.
1-Water Boiling kettle.
The heating coil has been added and a trial run is ready.
Modelling the flow pattern of a hair dryer is some thing intresting to see, this is just a trial run. The output velocity that was assumed is unrealistic. The next aim is to apply a heat flux to the heating coils and see the resulting temeprature field.
3-Refrigerant expansion valve .
5-BMW Formual F1 Racing Car.
almakky at hotmail dot co dot uk
A dot al-Makky at warwick dot ac dot uk
(This will be active till my registration ends)
Room CS 321
Center for Scientific Computing
University of Warwick
Gibbet Hill Road
+44 (024) 7615 0579