All Questions
Tagged with computational-physics computational-geometry
13
questions
2
votes
1
answer
205
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Need help with the python code: Calculating Madelung constant CsCl crystal structure
Need help with the code to estimate the Madelung constant for CsCl lattice:
Cs at (0,0,0)
Cl at (0.5, 0.5, 0.5)
Answer: Converged value I am getting is 0.465. ...
- 21
0
votes
0
answers
135
views
Adding stability to MPM simulation?
I am writing a 2D implementation of MLS-MPM, I have fluids working perfetly fine, solids technically work as well, at low time steps.
This is the fluid simulation at a large time step:
https://i....
- 273
0
votes
1
answer
113
views
Aerofoil study using CFD, struggling to find aerofoil coordinates
I’ve been messing around with Ansys and I’m struggling to find the aerofoil coordinates for a NACA 66-012?
I looked on Airfoil tools, but it doesn’t allow you to generate a 6 series aerofoil, only 4 ...
- 1
1
vote
2
answers
894
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Dyadic operations, fourth order tensors and Tensor algebra
I am trying to understand the dyadic operation for a while since I am interested in Elasticity problems. I believe an intuitive understanding (rather than assuming) will give me good problem solving ...
0
votes
0
answers
80
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How to distinguish primary hosts (stars) and orbiting satellites (planets) and tertiary bodies (moons) by their mass and trajectory?
I posted this question in the astronomy stackexchange. There are no responses, and it was suggested that I pose the question here. The "too long, didn't read" was taken from a comment, and ...
- 11
0
votes
1
answer
110
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Applying weak form
I have two dimensional equation and I want to solve it using Finite Element Methods.
$$ \nabla . (\alpha(x,y)\nabla u(x,y)) + \dfrac{\partial u(x,y)}{\partial x}+\dfrac{\partial u(x,y)}{\partial y}+u(...
40
votes
23
answers
10k
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Good examples of "two is easy, three is hard" in computational sciences
I recently encountered a formulation of the meta-phenomenon: "two is easy, three is hard" (phrased this way by Federico Poloni), which can be described, as follows:
When a certain problem is ...
- 8,702
7
votes
1
answer
868
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Putting N hard spheres randomly in given volume
I need to put $N$ spheres with given radius $R$ randomly in a Volume $[-0.5,0.5]^3$, without any overlap of spheres.
If I choose values so that all the spheres will occupy ~57% of the total volume, I ...
- 153
7
votes
2
answers
5k
views
Efficiently finding all (x,y,z) points within certain distance of point P
I am using Python, and I have a Pandas dataframe with hundreds of thousands, if not millions, of $(x,y,z)$ coordinates. I am looking to find an efficient method to index the original dataframe so that ...
- 213
2
votes
0
answers
67
views
How to model pedestrian flow through subway systems?
I'm a New Yorker and take the subways every day. I have a growing interest in understanding the distribution of paths people take on the subways to work every day.
I.e. if there are $n$ subway ...
- 145
1
vote
1
answer
148
views
What is a good algorithm, and framework, to calculate centres of gravity or mass (cog)?
I'd like to take an photograph, subdivide it into a tesselation, either of squares, or (ideally), hexagons, and then find the centre of gravity (or, if you prefer, centre of mass) of each cell of the ...
- 123
0
votes
1
answer
71
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How to model waterflow when only a couple of sample points available
Figure below depicts a cross section of a creek for which I am trying to measure the water flow for that section. What we have as inputs are a bunch of sample points on the river. For each sample ...
- 101
2
votes
1
answer
163
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Inclined plate capacitor grid/ mesh
You can calculate the electric potential over every point in a defined space by solving Laplace's equation. To do this in a computer program you set up an 2-d array/ matrix and loop the internal ...
- 145