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location London, United Kingdom
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visits member for 2 years, 9 months
seen 17 hours ago

My background is in theoretical/mathematical physics [MPhys/PhD], I was a Senior Computational Fluid Dynamics Analyst in the nuclear/defense industry before selling my sole and becoming a full-time commercial software developer around 2011.


Apr
10
revised Magnetic Pole Emission from Pulsars
deleted 4 characters in body
Mar
24
comment Many times speed of light
You ask a good question, one whose answer lies in the subtle difference between expansion that is faster than the speed of light and the propagation of information that is faster than the speed of light. The latter is forbidden by fundamental physical laws, but the former is allowed; that is, as long as you are not transmitting any information (like a light pulse), you can make something happen at a speed that is faster than that of light.
Mar
13
comment Was Einstein wrong when he said nothing can go faster than the speed of light?
I am pretty calm fella. Thanks for your concern though...
Mar
12
awarded  Talkative
Mar
12
awarded  Informed
Mar
12
comment Was Einstein wrong when he said nothing can go faster than the speed of light?
God, what has happened to this site. Daniel Shawen's answer below has more downvotes than this utter garbage. I feel sick...
Nov
21
comment Are Stephen Crothers' claims legitimate?
't Hooft is a top top guy.
Nov
11
answered Calculating Length Scales from Passive Scalar Field
Nov
6
answered What is the linearized form of relativistic hydrodynamics?
Oct
28
comment How important is mathematical proof in physics?
Thanks for clarifying...
Oct
28
comment How important is mathematical proof in physics?
I am not sure it is right to say 'proof checking software itself is a simple parser that can be reduced to one or two pages of code'. This is a massive underestimation. I only know of proof checkers for pure logic and these programs will not be as trivial as one or two pages of code...
Oct
17
comment Are Stephen Crothers' claims legitimate?
He also was inexplicably rude to Kerr in their correspondence, the guy contacted me when I was doing my Ph.D. hes papers are flawed at the very basic level - assumptions. One of his claims is that r is not a radial distance - well who ever said it was??
Oct
9
comment $\gamma$ in Newton's Second Law of Motion in Differential Form
The down vote is non-sense. Tell me the reason. This site makes a mockery of StackExchange.
Oct
9
revised $\gamma$ in Newton's Second Law of Motion in Differential Form
added 141 characters in body
Oct
3
comment $\gamma$ in Newton's Second Law of Motion in Differential Form
This is a Newtonian equation taken at face value. A classic introduction to aerodynamic drag for basic Newtonian physics is to use $\lambda v^{2}$ and there is nothing wrong with doing so. This clearly is not an advanced equation and all I am doing it answering the question, not second guessing what the author of the equation was thinking at the time of writing.
Oct
3
answered $\gamma$ in Newton's Second Law of Motion in Differential Form
Sep
23
comment How fast would a spaceship have to go to reach Alpha Centauri within a person's lifetime?
Note. The full special relativistic calculation with effects of acceleration has been answered here.
Sep
4
comment A way to track a gas's expansion
"Fumes with color" do you mean using tracer particulate? There is no microscopic way to trace gas molecules experimentally. What you have already (using an advective scalar quantity (a tracer) is the best you can do, moreover, the rapid expansion and the diffusion you see is actually a good representation of what the bulk flow of the gas will do macroscopically.
Sep
3
comment simple MHD simulation code for (self) education and play with
You seem to be suggesting that to write your own 2D MHD solver will be easy. It won't. I would start by reading about ideal MHD and Hyperbolic Methods for systems of conservative equations, namely Godunov-type methods. A good scheme to start with would be the HLL solver. I would start by writing a 1D solver for ideal hydro-dynamics, then 1D MHD. once you have a good class (if using C#, or C++) or method base (FORTRAN et al.) then you can extend the solver to work on a 2D grid. The HLL scheme above is very diffusive and thus you should not have to deal with excessive instability issues.
Sep
3
comment What is the drag coefficient of an open wedge?
To be 100% on the drag coefficient you will have to dig out some correlation for the open wedge case (this may not be easy, but it will have been done - unfortunately I don't have a reference to hand). However, depending on your application, you can use the same drag coefficient (DC) as the standard wedge, and argue that the use of this DC will be the pessimistic case. This could be true if, say you wanted to find the resistive force on the object for some flow speed. In this case the use of the closed wedge DC would be pessimistic and justifiable as the DC on the closed case will be smaller.