Questions tagged [simulations]
The imitation of a real-world process using an analogous process that is easier to control and experiment with.
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Visualizing helium’s interacting electrons
I want to numerically simulate the experimental results seen in this Phys. Rev. Lett. paper, specifically the interference patterns of ionized helium. The authors used photoionization microscopy to ...
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Are any mathematical constants justified, is a universal equation defining them all even possible? [closed]
Alright. I know this is way too philosophical right off the bat. What I can't get around are the mathematical constants, where they came from, and why they are so fine tuned. In "newer" ...
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Using Crank-Nicolson to solve Non-Linear Schrödinger equation in Python [closed]
I aim to solve the (non-linear) Schrodinger equation using the Crank-Nicolson method in Python. Here are my two functions.
...
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What aspects of GR should be taken into consideration for realistic visualizations of a Kerr black hole? [closed]
I am not 100% sure if these kinds of questions are allowed, if not sorry in advance.
For the past year, me and a friend have been working on a render engine to visualize a Kerr black hole. We have ...
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Lagrange multipliers method for a bead on a parabola-shaped wire [closed]
I have this simulation problem that looks very easy at first look (and maybe it is, especially using Lagrange equations of the 2nd. kind). I am using the Lagrange multipliers and I am kinda not sure ...
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Material Point Method (MPM) applied to wave simulation problems?
MPM combines elements of both the finite element method (FEM) and the particle-based methods. It is particularly suitable for problems involving large deformations or fluid-solid interaction. Would ...
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Two-Body Problem as a function of $t$
I'm writing an orbital simulator program and I'm struggling to apply the two-body problem.
To simulate it properly I need values for the $x$, $y$, and $z$ coordinates for both bodies. Ideally, these ...
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Writing a Monte Carlo radiative transfer simulation for computing the observed blackbody radiance due to the environment
Background
I'm attempting to determine the power observed at some antenna immersed in some perhaps highly anisotropic scattering and absorbing medium due to the blackbody radiance of the environment. ...
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What is the equilibrium distribution for the Lattice Boltzman Model on a hexagonal grid?
I'm trying to implement a lattice Boltzmann model fluid simulation, but I'm having trouble implementing it right now.
Every source I find seems to give a different equilibrium distribution and I don't ...
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Molecular Dynamics | Calculating Haven coefficient
So i have following problem: I have some structure with 106 particles of oxygen in it, which is responsible for ionic conductivity in this structure: what I want to achieve is to calculate the Haven ...
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Derivation of Pressure Correction Term in Lennard-Jones Fluid Simulation
Context
Hey everyone, I'm working on a molecular dynamics assignment where I'm simulating a Lennard-Jones fluid in the Gibbs ensemble. The potential is given by equation (1):
$$
U(r) = 4\epsilon \...
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I need a must-have reference or handbook about the numerical solution of the 3D wave equation
I'm looking for an encyclopaedic book on numerical simulation of the 3D wave equation.
One that is a must-have reference with finite differences, finite element and spectral methods.
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Trouble simulating/ray tracing a simple microscope
I'm trying to run a (seemingly) simple simulation of a basic microscope using the free software WinLens 3D Basic, but the ray tracing looks wrong:
The microscope consists of a small plano-convex lens ...
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Seeking Visualization Tools for Hypothetical Black Hole Concept
I have a idea I'd like to explore: If a black hole can bend light due to its immense gravitational attraction, could we imagine an 'inverted black hole'? In this hypothetical scenario, this object ...
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The 'core-cusp' problem for dark matter halos in larger galaxies
TLDR: Do observations of larger galaxies favour 'cuspy' dark matter halo distributions, as predicted by N-body simulations?
I've been trying to understand the 'core-cusp' problem for dark matter halos ...
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Non-dimensionalisation of Navier-Stokes Equations [closed]
I am trying to numerically simulate a flow in which a fluid with kinematic viscosity $\nu=0.00001167$ m$^2$/s is injected into a cylindrical tube of diameter 0.00745m at a velocity of 45.9 m/s. Thus, ...
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Good text for writing a realtime physics solver?
What is a good, up-to-date, well-regarded text on writing physics solvers for (e.g.) game engines or realtime simulations?
In particular, treatment of numerical stability, convergence, asymptotic ...
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Simulator to simulate the intereference between light and the wave produced by an electron driven by the light
When an electromagnetic wave reaches an electron the electron will oscillate creating it's own electromagnetic wave which will interfere with the original electromagnetic wave. I am looking for a free ...
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MEEP Simulation of Two Sources
I am trying to code up a simulation of a light source passing through a refractive waveguide under a static electric field. I adapted the fields in a waveguide code (https://meep.readthedocs.io/en/...
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Droplet Breakup model solely for charged droplets in electric field?
At the moment I am trying to simulate charged droplets and their berakup in an homogeneous electrical field in vacuum. I am using a VoF-Method, but as the droplets get smaller and smaller I would need ...
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Is there any game for understanding elevator physics?
I'm a physics teacher and I'm wondering if there's any game for physics elevator problems (weight in accelerating elevator) that the student can play with to better understand in what situations the ...
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Effect of projectile movement inside the coil launcher
I'm simulating a simple coil launcher system where there is a round coil , a capacitor and a round projectile which at first is placed at the start of the coil.
so the whole circuit is a simple RLC ...
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Seeking Resources for Implementing Self-Consistent Numerical Calculation of Retarded Green's Function
I'm seeking resources or references to learn how to implement a self-consistent numerical calculation for the retarded Green's function $G^R(\vec{p},E)$, which is defined as:
$$
G^R(\vec{p},E) = \frac{...
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Electrical and Electronic circuits simulation using Maxwell's equations
How can the Maxwell equations be used for developing exact mathematical model of electrical and electronic circuits?
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Simulation of electric water heater system [closed]
I'm want to write a simulation for an electric water heaters in python. As of my current understanding of thermodynamics, I have started from the energy balance equation for open systems:
$$
dT = dH - ...
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Compton Scattering Angle Distribution, and the Klein-Nishina Model
I have a Geant4 simulation where 662keV photons are going into a detecting volume (Germanium). As expected, when I look at the output of the simulation, these photons undergo Compton scattering and ...
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How to calculate pressure $p$ in the Navier-Stokes equation to simulate the time evolution of a fluid?
I wanted to simulate the motion of a fluid (continuously filling the entire space) in a given space, say $3$-dimensional Euclidean space. To calculate the dynamics of fluid motion, I used the Navier-...
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How to numerically solve non-linear 1D diffusion equation in time-domain?
The equation to be solved is this:
$$\frac{\partial H_y(x,t)}{\partial t}=\left(\frac{1}{\sigma\:\mu(H_y)}\right)\frac{\partial^{2}{H_y(x,t)}}{\partial{x^{2}}}$$
But note that the magnetic ...
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Thermal simulation of conduction between metal and air
I am building a (2D) thermal simulation and the situation can be simplified as follow :
A room filled with air at a uniform temperature (say 20 celsius) and on the floor, a plate of copper at a ...
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(Weakly compressible) Smoothed Particle Hydrodynamics (SPH) and speed of sound
In SPH (weakly compressible approach) the Cole state equation is used to compute pressure from density:
$$p(\rho)=\frac{\rho_0c^2}{\gamma}\left(\left(\frac{\rho}{\rho_0}\right)^\gamma-1\right)+p_0$$
$...
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How does convex splitting method work?
I'm an undergraduate physics student and I'm simulating some partial differential equations using finite element method. For non-linear equations I found a method called linear convex splitting ...
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Extreme Kerr render engine issue
So, me and a friend have been working on a Kerr render engine. It uses the Kerr metric of general relativity to draw the image of a black hole. Our current results look like this;
The accounted for ...
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Power spectrum of a vector field
I am looking for a clear definition for the power spectrum of a vector field.
In the literature I've found this expression:
$$ \langle \tilde{\boldsymbol{v}}(\boldsymbol{k}) \cdot \tilde{\boldsymbol{v}...
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How to create an image of a velocity field representing Kolmogorov structure function?
I want to create a two-dimensional image where each pixel represents a velocity. The velocities are distributed in such a way that if you plot a function of separation between all unique pairs of ...
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Is it true that particle-in-cell (PIC) simulation apply both Lagranian/Eulerian method in?
I'm learning about particle-in-cell (PIC simulation) of plasma and I'm having some questions on the description of PIC method. I still have somes questions how PIC simulation works with Eulerian and ...
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What is the difference between Lagrangian and Eulerian description in Plasma?
I'm going to study plasma characteristics by using Particle-In-Cell (PIC) method and I know that plasma has fluid behaviour and can also consider as particle behaviour also. To understand a basic of ...
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Inertias of the drivetrain components of a 4x4 vehicle or any geared system for that matter
I’m making a vehicle simulator and I’m not entirely sure if my inertia calculations are right or are completely wrong. What I currently have now is something like this:
1. Engine:
engine_Out_Inertia =...
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Numeric Solution vs Analytic Solution (1D Quantum Harmonic Oscillator)
We probably all know the analytic solution of the 1D Quantum Harmonic Oscillator is given as follows:
$$\Psi_n(x) = \dfrac{1}{\sqrt{2^n\,n!}}\,\left(\dfrac{m\,\omega}{\pi\,\hbar}\right)^{(1/4)}\,e^{\...
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Books and review articles for numerical relativity?
What are good books or review articles to read for numerical relativity?
I have read some textbooks on the 3+1 formalism (such as the book by Baumgarte and Shapiro), but I would like to have a ...
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A unit of time $\frac{GM}{c^3}$ [closed]
I have come across a time unit $M$ that should be equal to $\frac{GM}{c^3}$. I cannot find anything at all about this anywhere.
I came across it while doing flux analysis on the flux from black hole ...
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Optical software - thin film interference
I am currently using a software called "SCOUT" to thin film interference simulation, and I would like to know if there is a better software to do this type of simulations. My goal is to vary ...
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Kinetic Monte-Carlo Simulation to solve master equation
Kinetic monte Carlo can be used to simulate Master equation for Markov processes.For simple 1D random walk the master equation is -
$$\frac{\partial P(n,t)}{\partial t}=pP(n-1,t)+qP(n+1,t)-(p+q)P(n,t)$...
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Question about Monte Carlo Simulation of 2D lattice Ising Model and Classical Heisenberg Model
I'm trying run and experiment with Monte Carlo Simulations of 2D lattice Ising Model and Classical Heisenberg Model.
I've made a brief research on both models and I saw that main differences of these ...
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How to numerically simulate a rolling object? [closed]
I am a maths person and definitely not a physics person, so maybe this is taught somewhere and I haven't learned it. I am trying to understand and figure out how to simulate rolling an object on a ...
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What does a mode mean in the context of Quantum Transmitting Boundary Method (QTBM)?
The problem statement in the original paper by C.S.Lent and D.J.Kirkner says:
Given: The total energy E, the potential energy in each region, $V_{i}(x,y)$, $i=0,1,2,...,n$, and the complex amplitudes ...
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How can one model squeezed states in 3D optical modelling software?
I would like to model squeezed light and its evolution (such as when passing through lenses after being generated) using optics software such as OptiFDTD or ZEMAX. However, I don’t see any way to make ...
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Veracity of light field propagation simulation method (Combined Split-step Fourier and BPM)
When trying to simulate light propagation in three spatial dimensions and one temporal dimension I encountered a method given in this thesis. Here (on page 32), it is proposed to do a BPM within a ...
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Mapping an arbitrary spin graph to one with nearest neighbour interactions
I remember having heard once that generic spin-graphs e.g. Ising, or at least 2-local ones (defined as the Hamiltonian contains pairwise interactions at most), can always be mapped to one another one (...
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Computational difficulty of simulating charge distributions on highly asymmetric surface?
I am wondering if anyone happens to know the computational methods - and hence the computational complexity - of simulating the distribution of an electric charge (how electrons distribute) over a ...
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Compute the forces affecting a fish swimming in a water in an efficient way, without computing the dynamics of the whole fluid [closed]
I wish to implement a computer simulation of fish swimming in water in a best-effort physically accurate way.
I would need this simulation to be fast. This means that I can't simulate the dynamics of ...
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