I’m John Stone and This Is How I Mesh

John Stone of CFD Technologies.

John Stone of CFD Technologies.

My home town of Manchester, England is notable for many reasons: the development of Graphene, Emmeline Pankhurst, Sir Joseph Whitworth (the father of precision engineering),  Rutherford’s splitting of the atom, and Alan Turing’s work at the University of Manchester, to name but a few.

Apparently it also has a good football team.

I studied aeronautical engineering at Manchester University, near the lab that Rutherford worked in, and opposite Whitworth Hall, in which I had my graduation. Two years ago I was back there to see my daughter graduate as a maths teacher in the same building, and it was even better the second time.

I loved maths and physics at school, but it was my fascination with Concorde that piqued my interest in aeronautics. To this day I still regret never having had the opportunity to travel on it. I remained at Manchester University to study for a PhD, and that’s when I discovered CFD. I have worked in this field for 30 years now. It has been an incredible career which has introduced me to amazing people and places. After university, I journeyed across the Pennine hills to Sheffield for a job with Flow Simulation (later Fluent) where I worked on the development of RAMPANT with Wayne Smith at Creare in New Hampshire. These were massively exciting times. I felt privileged working in this breakthrough field when an academic technology was being adopted by industry. Also during this time came marriage, children and plenty of travel. I loved development, but had the opportunity to move into sales at Fluent. Ferit Boyson, the director, was a fantastic mentor and I learnt a lot from him. I excelled in sales and became sales manager before moving to CD-adapco in London for a short while.

A desire to run my own business became overwhelming, so I moved back to Sheffield and set up CFD Technologies in 1998. In 2000, I also became UK distributor for Pointwise, after discussions with Rick Matus, who I had worked with previously at Fluent in New Hampshire. Pointwise has been a truly excellent partner to do business with for the past 16 years and provides a product and support that are second to none. The distributors meet annually to discuss new features and it’s an opportunity to give feedback from our UK based clients.

More recently, CFD Technologies added the solver CFD++, and together with Pointwise, provides a total CFD solution.

  • Location: Sheffield, England
  • Current position: Partner CFD Technologies  
  • Current computer: Lenovo Y50-70 Laptop, Intel core i7, 16GB RAM, 1TB + 8GB SSHD
  • One word that best describes how you work: Focused

All hell could let loose beside me when I am working and I wouldn’t notice. Multi-tasking is not for me. Also, my family tell me it’s a similar phenomenon that occurs when I’m watching sport on TV.

What software or tools do you use every day?

I use Microsoft Office 365 when I’m in the office for daily admin tasks, keeping track of customers and writing reports. Away from the office the iPhone is indispensable for email, calendar and as a satnav using Google maps. GoToMeeting is brilliant as it saves on so much travelling time. It’s essential to get together with colleagues/clients from around the world with ease.

What does your workspace look like?

John's current workspace.

John’s current workspace.

I have just invested in a very comfortable chair. I have reached that point where I need glasses for reading, so I find a large monitor/screen a must. I am so focused on my screen that my surroundings aren’t too big of an issue for me. However, I still have a picture of Concorde from years ago, a print of Manchester United winning the Treble and my karate 1st Dan certificate, just because they have always been there. My phone is a very important tool for me as I provide a lot of support, so it’s always at hand.

Recently some friends bought me a “What would Elvis do?” sign. I have always been a fan (much to my wife’s annoyance) and it’s a good reminder to “stay cool” while working.

What do you see are the biggest challenges facing CFD in the next 5 years?

Each industry sector has its own challenges. For some, it’s a matter of improving their solution accuracy when there are complex physics involved, while for others it’s about getting results within project timescales.  This can be a challenge due to the complex nature of their geometry. A common issue for most industries is making CAD geometry CFD ready. Pointwise has made great strides in this area with their solid meshing technique.

What are you currently working on?

The beauty of this job is the sheer variety of industries and applications. I am currently providing support to defense and aerospace clients in addition to helping a user mesh a fridge full of pastries! As is the case with all support, I cannot share these. I travel frequently to visit clients, provide training, and am presently preparing for a marine OpenFOAM user day in London.

We are also gearing up for the release of Pointwise V18, which is very exciting. I’ve been using the beta version for some time now. The software is extremely stable and I’m confident that the new features will be well received by our users. The V18 picture below shows the quad dominant surface mesh on the back end of a mortar with many layers of blue hex cells grown off the walls using T-Rex and in the wake.

Quad dominant surface mesh with hex cells generated using T-Rex.

Quad dominant surface mesh with hex cells generated using T-Rex.

What would you say is your meshing specialty?

I get great feedback from clients about the level of support we provide and this makes me feel very proud. I don’t really have a meshing specialty, but having been around meshing and CFD for so long now, there are not many CFD problems that can’t be solved.

Any tips for our users?

Don’t suffer in silence! If you need support, please ask. Sometimes it’s a really easy solution (granted, not always). Many features of Pointwise are nicely explained and demonstrated with many videos on Pointwise’s YouTube channel, CFDMeshing.

What project are you most proud of and why?

I am most proud of setting up my own company and am very lucky to be doing a job I really enjoy.

With regards to CFD, in early 2015 I was helping a new client to study their centrifugal pumps. A Pointwise Glyph script was written to read the blade, hub and shroud curves then create the corresponding 3D surfaces, including a periodic surface. A fully structured hex mesh is then automatically generated with a very nice C-Grid topology around the blade. The script was extended to set the CAE boundary conditions and export to the CFD++ solver.  In the end, a high quality multiblock structured mesh consisting of 330,000 cells was generated.

This image illustrates the process of importing profile curves, creating surfaces, and automatic mesh generation using a Pointwise Glyph script.

This image illustrates the process of importing profile curves, creating surfaces, and automatic mesh generation using a Pointwise Glyph script.

The setup of the model in CFD++ was done manually using its easy-to-use GUI shown below. However, the input file created can be used again.  The incompressible flow equations were solved with the 2-equation k-e realizable turbulence model with wall-functions. A single rotating reference frame was used. The boundary conditions were setup with an inlet mass flow rate, an outflow back pressure and periodic boundary conditions. Initial conditions were set to zero velocity everywhere. Some post-processing options were enabled in order to calculate the average total head at the inlet and outlet boundaries, and the mass flow rate at the outlet (a 2nd convergence check).

Model setup within CFD++ and solution visualization.

Model setup within CFD++ and solution visualization.

The model was run on 4 cores of an i7 Windows laptop. The solution was set to stop iterating once a 5-order reduction in the residuals was accomplished, which took 202 iterations. The wall clock time was just 19 mins. The pressure contour on the blade mid-plane is shown above and the total head rise is output. This particular project impressed me since we were able to go from curves to a CFD solution in just 31 minutes. Further runs were carried out 10 minutes quicker using the CFD++ input file created from the first setup.

What CFD solver and postprocessor do you use most often?

The solver that I use most often is CFD++. Its accuracy and ability to provide results for challenging flows with complex physics and moving bodies is what sets it apart from other general purpose software. It has had overset capability for over 10 years which is very robust. For some years I’ve used OpenFOAM as there are many Pointwise users with this solver. I use ParaView and CFD++ visualizer for viewing results.

Are you reading any interesting technical papers we should know about?

Recently I’ve been reading John Steinbrenner’s Construction of Prism and Hex Layers from Anisotropic Tetrahedra which describes Pointwise’s T-Rex cell combination techniques. The last paper that I read was Meshing Consideration for Automotive Shape Design Optimization (SAE 2016-01-1389) by Travis Carrigan, Mark Landon and Claudio Pita. The meshing technique used in the paper was ideal for a company that I’m currently working with.

Do you plan on attending any conferences or workshops this year?

The NAFEMS Seminar – A guide to Hybrid RANS-LES methods: Industrial Examples and Theory, held in Oxfordshire last September was a good one, so I will keep a look out for other NAFEMS CFD conferences to attend. I always bump into people that I’ve not seen in a while and it’s great to catch up with them. The Pointwise User Group Meeting and distributors meeting in Texas is always rewarding and productive, and I look forward to the next meeting in September.

This year I’ve presented at a few OpenFOAM seminars and we held a Pointwise workshop in Bristol last September.

What do you do outside the world of CFD?


I have to counteract sitting in a comfortable chair all day somehow.

I have been playing 5-a-side football (soccer) with a group of guys for almost 20 years now. It’s quite a mix of people: firemen, doctors, barristers and me. We are all struggling with age related injuries most weeks. But what I lack in skill these days I make up for in brute force. Some of our sons are now beginning to join us. They try to outrun us, but I’m still an excellent defender, and my intention is to take the ball not their legs (honestly!).

I have been involved in karate and rugby most of my life, but recently swapped them for the more sedate sport of badminton.

I love to travel and have been lucky enough to drive along both the Atlantic coast of Ireland and the Pacific coast of USA (from San Francisco to Los Angeles) both were absolutely breath-taking. I spend a lot of holiday time in Spain, waking early for a run while it’s still cool, and enjoying long lunches with tapas and Rioja. I’m fairly happy to accompany my wife to museums and galleries, but absolutely no shopping, anywhere, ever.

Reading about the following areas of history has become a relatively new obsession (I love a good battle): War of the Roses, Roman Empire, Vikings, and Genghis Khan. This is strange really, as I hated history at school.

What is some of the best CFD advice you’ve ever received?

Simplify! Don’t try to model every little detail if it’s not relevant to the overall aim of the simulation. Use symmetry, where there is any, and take out small details that have no effect on the results, as they just increase the mesh size and the runtime.

If you had to pick a place to have dinner, where would you go?

We live on the edge of the Peak District National Park and there are numerous traditional, country pubs serving great, rustic food. One of my favourites is the Cricket Inn. On a fine summer’s day you can sit outside and watch the local cricket team play, while enjoying their seafood platter washed down with a pint of Guinness. On a normal British day, I sit by the log fire and eat their steak and ale pie (which, incidentally, also goes well with Guinness).

For a night out in Sheffield city centre, Piccolinos Italian is special. And for French food we love Le Bistrot Pierre. Unfortunately, I have never really found a great place to eat Indian or Thai food in Sheffield. For that treat, I have to go back to Manchester and the Chaophraya.

About Travis Carrigan

A Pointwise engineer helping other engineers solve their meshing problems.
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