Progress in CFX

Last term we did an introductory course for ANSYS CFX and I found it really interesting. ANSYS CFX is a computer package with which you can design an object, then create a mesh to cover it (imagine a spider's web stretched over the object) and then you can set parameters and things and tell it to model what would happen if water came in one end, air through the top and there was just one outlet pipe (for example). Then as if by magic the program thinks about it for a while and gives you an answer.

Well now we have to do some coursework using it, it's not due until May and today I started it finally. I've been trying to start it for the past 4 weeks now, but all my attempts have been thwarted by the problem of a locked door. There is just one room in the whole university that has CFX computers in apparently and as CFD Masters students we are allowed to go in there. Only the door is always locked. It took two weeks to ascertain who was going to be allowed to give us permission to go in there. Then that person was off sick, then he was in meetings for most of last week. Well today I caught up with his secretary again and found out that the room is meant to be unlocked in office hours and that we can go in whenever we want, so long as there isn't a class in progress. Hurrah!

So I spent an hour or so playing with a piece of software I learnt a little bit about 3 months ago and haven't been able to touch since. On my third attempt I managed to complete the basic design for the object we were told to create. I meshed it first time without any problems. Then I tried to open it in what they call the Pre-Processor. I failed. It's got the wrong file extension and I have no idea how to convert it to the correct one. I can't recall that we were ever told how to go from meshing to pre. This is frustrating. I'm hoping that someone else in my class knows and can show me later in the week. This should not be a problem considering we're now allowed in the room Mon-Fri, 9am-5pm.

The world through the eyes of a mathematician

I will begin as I have done previously with a quote from Ian Stewart's letters to a young mathematician.

"I am reminded of one of the many stories mathematicians tell each other after all nonmathematicians leave the room. A mathematician at a famous university went to look around the new auditorium, and when she got there, she found the dean of the faculty staring at the ceiling and muttering to himself, "...forty-five, forty-six, forty-seven..." Naturally she interrupted the count to find out what it was for. "I'm counting the lights," said the dean. The mathematician looked up at the perfect rectangular array of lights and said, "That's easy, there are ... twelve that way, and ... eight that way. Twelve eights are ninety-six." "No, no," said the dean impatiently. "I want the exact number."
Even when it comes to something as simple as counting, we mathematicians see the world differently from other folk."

People the world over see things differently, but I find that more often than not mathematicians/scientists see the world in a similar way to each other, but in a totally different way to an artist or a musician.

I wonder why we see things differently. Do we see things differently because of our different interests? Or are we interested in different things because we see things differently?

It's like the chicken and the egg saga. Which comes first? Is it instilled in us from birth? Are we genetically programmed to be like we are? Do environmental factors play a part at all?

I don't know the answers, but it does make interesting thinking. For me anyway. But is that because I'm a mathematician? I have no idea if an artist would find this idea interesting or not.

Sharon Evans, licensed to do Mathematics!

Before I got far into Ian Stewart's book Letters to a young mathematician I came across the following passage, which amused me so much I feel obliged to write about it.

We all know that our doctor has a medical degree, and our lawyer has a law degree, because those are specific, well-defined professions that require equally specific training. But you don't find brass plaques on buildings advertising a licensed mathematician within, who, for a large fee, will solve any math problems that you need help with.

He goes on to comment that mathematicians and maths are not noticed in the real world. Basically what we do and who we are is taken for granted. People assume that their computers are all the work of computer scientists, but they don't necessarily realise that a lot of computer science is actually maths. A lot of gene technology is actually maths and we wouldn't know much about space (or our own world) if it wasn't for mathematicians of the past.

I find it frustrating sometimes when I tell people I'm a maths student. The blank look on their face along with a certain amount of fear in their eyes. They often say that they could never do it because they were never any good at maths in school. If I had believed my primary school teacher Mrs H, maybe I would also be one of them. Maybe I wouldn't have a degree in maths if I had believed her. A small part of me wants to go and find her and show her my degree certificate and say,

"do you know what Mrs H, I got a degree in mathematics despite you telling me I'd never get anywhere unless I learnt my times tables..... and I still don't know them!"

The thing is the stuff you learn in maths classes at school is mostly how to add, subtract, times and divide things. There is also a lot of other stuff, but at university level you get told to forget most of what you've been taught so far because a lot of it was just lies. They tell lies to kids in school about maths (and other subjects) because the truth is just too complex to cover in the time they have your attention for. Also the range of maths is much broader once you get to university level.

At most universities (certainly in the UK) there will be the option to study some statistics, some pure mathematics (algebra and calculus - i.e. lots of funny letters and symbols instead of "proper numbers") and of course applied mathematics. Applied mathematics can cover a whole range of topics from the mathematics of biology (why tigers have stripes and how disease spreads) to discrete mathematics (binary code, password quality, code making/breaking etc) or mechanics (movement of solids, or indeed liquids or gases).

Of course there are also many other applications of mathematics. If I were to mention all of them here this post may never end.

My course falls under the engineering department, but I still class myself as a mathematician. A lot of what I do is still mathematics. I think that I will always think of myself as a mathematician. No matter how much I learn about engineering or whether or not I get a job in my field. Deep inside me is the heart of a mathematician and it skips a beat when I read about a particularly exciting concept or solve a big problem.

Masters Summer Project

I have to choose a project to do for my Masters in CFD over the summer this year. We've not been given the list of titles yet, but I've been thinking about the kind of thing I'd like to do. I'm really into bubbles and I also like two-phase/multi-phase flow. So I'd like to do something along those lines as it would be interesting for me. Hopefully it will also be useful for me in the future too. That depends on what I do in the future though.

So the summer project. In an email from one of the professors the other day is one of the proposed titles. "CFD Simulation of Droplet Formation in Membrane Emulsification."

The word "droplet" caught my eye straight away as that fits into the whole multi-phase flow idea that I like. Plus a droplet of liquid in air is the opposite of a bubble really, if you think about it. So I googled for "Membrane Emulsification" and got this website. That has a really simple diagram showing something that I assume would be a similar sort of set up to what they would like the student to model for the project.

How amazing is that? I think it's fascinating!

Turbulence

Our lecturer quoted this poem by Lewis Fry Richardson when talking about Turbulence a few weeks ago.

"Big whirls have little whirls that feed on their velocity,
and little whirls have lesser whirls and so on to viscosity."

The poem was inspired by this one by Jonathan Swift.

“So, naturalists observe, a flea
Hath smaller fleas on him that prey
And these hath smaller fleas to bite ‘em
And so proceed ad infinitum.”

The turbulence poem is quite clever as it encapsulates quite well the theory of turbulence. Another cool thing he showed us was this picture by Leonardo da Vinci. Which is quite an amazing drawing.

I find turbulence really quite fascinating and I'm glad that my lecturer showed us these interesting things that are related as it will help me remember what is happening.

If at first you don't succeed - try harder!

In "Letters to a young mathematician" Ian Stewart writes something along the lines of

'if you do not understand a text you are reading, make a note
of it and carry on reading as the part you do not understand may be explained
later.'

I read that bit yesterday (I got the book for Christmas) and didn't really expect that I would be following the advice the very next day.