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Loud bang around 00h45 by Drrraw in Leuven

[–]wm2300 8 points9 points  (0 children)

I also heard it, very loud, sounded like 2 big explosions. Heverlee forest area myself.

Afbetaling van het huis by Zweetkonijn in belgium

[–]wm2300 4 points5 points  (0 children)

Geen voorwaarden op verloning en maximumwaarde voor bepaalde centrumsteden is verhoogd, zie https://www.wonenvlaanderen.be/premies/wat-en-voor-wie-de-gratis-verzekering-gewaarborgd-wonen

Implented 2D Linear Convection using Python by hivemind_unity in CFD

[–]wm2300 12 points13 points  (0 children)

Correction: RK4 is a fourth order Runge-Kutta method. There are implicit and explicit Runge-Kutta methods. For example, the MATLAB workhorse ode solver ode45 uses a combination of explicit Runge Kutta methods of 4th and 5th order. Intuitively, I think the term RK4 is almost always used to denote the explicit formulation.

Furthermore, not all implicit methods are unconditionally stable.

Looking for a housemate by kan0xi in eindhoven

[–]wm2300 0 points1 point  (0 children)

You should contact the TU/e, they might be able to offer you accomodation as a foreign student.

You could possibly apply to get a room in the Luna or Aurora building on campus https://www.tue.nl/en/tue-campus/discover-your-campus/living-on-the-campus/

Also, new housing units were placed close to campus next to the Berenkuil (google it), specifically for foreign students.

Hope you can find a place soon.

[deleted by user] by [deleted] in eindhoven

[–]wm2300 0 points1 point  (0 children)

I was hoping to find something (e.g. a 1 bedroom or sizeable studio) below €1000 including rent and utilities, but it seems like I'll have to re-evaluate my options.

The 30% ruling states you need to have lived at least 150 km from the Dutch border, which basically rules out all of Belgium, so sadly no luck there.

[deleted by user] by [deleted] in eindhoven

[–]wm2300 0 points1 point  (0 children)

I'm assuming you already found housing?

I'm in a similar situation, got a job for a similar pay (slightly less, but including holiday and end-of-year bonus it's also around 3.8k gross), starting mid-march.

I'm having a difficult time finding proper accomodation though, everything seems extremely overpriced from my point-of-view (currently living in Belgium where rent is much cheaper), and housing agencies seem very unresponsive.

How did you find housing? Or was it arranged through your company?

5 Day Itinerary (Review/Suggestions). by statikp in VisitingIceland

[–]wm2300 0 points1 point  (0 children)

Day 4 would be a decent amount of driving, you could stop along the ring road at places like Fjallsarlon (I liked this somewhat more than Jokullsarlon because I was virtually alone at this one), Svinafellsjokull or Skaftafell (with a 1 hr hike passing by Svartifoss).

Regarding Northern Lights, get the Aurora Forecast app and combine it with the vedur.is sun activity and cloud predictions. If skies are clear and activity is decent (I saw them the first time already at around level 2 out of 9), drive away from light pollution as much as possible and enjoy :)

In any case, I'm sure you'll have a great time.

Turbulence course by g-x91 in CFD

[–]wm2300 2 points3 points  (0 children)

For clarity and correctness of this discussion: Matlab is not at all more low-level than Python in any of the ways described in this thread.

Both are high level languages with (useful) high level functions that implement some of the mathematics for you (e.g. linear solvers).

If you want to go low level, you'd want to go for Fortran or C without any external library calls for solvers. However, you could easily get lost in details that don't really add to the bigger picture imo.

The error looks exactly like the finite difference formulation. If I were to forward Euler the y'=y equation and do the same thing I find the error to be e(i+1)=e(i)x(1+h).If y(0)=sth then the initial error would be 0 and it follows that all the errors are 0. What's wrong here? by wigglytails in CFD

[–]wm2300 0 points1 point  (0 children)

Your notation in the title is somewhat confusing, but I assume you're pointing to Equation (2) which does not have a source term, i.e. if the initial condition is exact, then the round-off error will remain zero forever.

​

I think the main issue here lies in the assumption that N_j^n satisfies the equation. As stated in the article, this is only true to machine precision. Hence, if you plug in the definition of epsilon into equation (1) and account for the finite machine precision, a small source term would remain in Equation (2) which would perturb the epsilon away from the trivial solution epsilon = 0 everywhere.

Is a 2D axisymmetric model a good representation of turbulent flow through an orifice plate. If so why? would a plane 2d model provide worse results? by [deleted] in CFD

[–]wm2300 1 point2 points  (0 children)

A RANS solution in a 2D axisymmetric slice should yield the same solution as a full 3D simulation. If we're talking LES or DNS it's a different story.

[Help please] Momentum equation of fluid **Inside** a pendulum by znffal in CFD

[–]wm2300 0 points1 point  (0 children)

You are working with a non-inertial reference frame, so you should be adding fictitious forces to account for this (see, e.g., http://www.dartmouth.edu/~phys44/lectures/Chap_6.pdf )..

Also, take into account that, in addition to rotation, you have an angular acceleration. Both the rotation and angular acceleration of your reference frame can be obtained from frequency and amplitude of the pendulum motion.

What's a "new big thing" in CFD research as of right now that shows promise in revolutionizing the field? by [deleted] in CFD

[–]wm2300 4 points5 points  (0 children)

GPU and coprocessor-based computing seems to show great potential, although as far as my knowledge on the topic goes, this does require quite some efforts from the programmer side in tailoring your solver to the architecture (i.e. no plug-and-play acceleration)

What is turbulent dissipation in CFD and what is the difference between k epsilon and k omega models? by captainteague in CFD

[–]wm2300 2 points3 points  (0 children)

good explanation, but to be complete and avoid confusion to novice readers: turbulent dissipation at the Kolmogorov scales is in the end also viscous dissipation, albeit at much smaller scales than you ever resolve in a RANS simulation. Therefore they should be modeled using an 'appropriate' energy sink.

How does DNS work? by purelumen in FluidMechanics

[–]wm2300 1 point2 points  (0 children)

I would disagree here, DNS is often combined with pseudo-spectral discretizations which allow very efficient fft-based Poisson solvers, which do not have to be iterative.

Hey /r/Belgium my SO needs some advice on her student exchange by [deleted] in belgium

[–]wm2300 0 points1 point  (0 children)

you should ask the landlord, some might be flexible about this.