Questions tagged [simulation]
Simulation is the process of mimicking the behaviour of a real physical process or system using a representative model.
219
questions
3
votes
1answer
36 views
Choosing an appropriate time step for a discrete & continuous dynamics simulation
I have inherited of a flight dynamics simulation in C++ which represents a small drone with it's autopilot, actuator dynamics and a solid state IMU.
Hence, it is composed of a few models, some ...
0
votes
0answers
30 views
Effect of Peclet number on concentration profiles
I have been performing convection-diffusion transport studies on microfluidic channels like the following
I came across an article that illustrates the effect fo Peclet number on concentration ...
1
vote
0answers
47 views
computing time scale and steady state concentration in microfluidic channels
I have been performing convection-diffusion transport studies on microfluidic channels like the following
The inlet concentration is specific and I obtain the time-dependent concentration profiles of ...
1
vote
0answers
53 views
Problems with simulation of a spatial filter 4f setup (Python)
I have a question about my code which computes numerically the output field of a 4f setup with a pinhole in the middle which works as a spatial filter.
My setup consists of two lenses with 50mm focal ...
0
votes
1answer
65 views
Extracting data from VTK simulations using C++
I have been given a few numerical simulations regarding fluid mixing and have been asked to extract a few parameters from them using C++. Altogether there are about 1000 VTK files per simulation, and ...
2
votes
1answer
78 views
Is the Immersed Boundary (IB) method a Direct Numerical Simulation?
Is the Immersed Boundary (IB) method considered a Direct Numerical Simulation?
A DNS code is the most detailed type of simulation and the most accurate but computationally expensive, right?
What makes ...
0
votes
0answers
32 views
Numerical simulation for a bounded process. Is slight deviation a “normal” fact?
Suppose I have to numerically simulate a process $\{y_t\}$ such that $y_t\geq0$ $\forall t\in\mathbb{N}$, with $t$ denoting time-step.
Let's suppose I use MonteCarlo with $\mathscr{N}$ simulation ...
1
vote
0answers
32 views
Discretization formula for a system of two differential equations. “Solution to one of these is the initial condition of the other”. In which sense?
Consider the following stochastic differential equation
\begin{equation}
dy=\left(A-\left(A+B\right)y\right)dt+C\sqrt{y\left(1-y\right)}dW\tag{1}
\end{equation}
where $A$, $B$ and $C$ are parameters ...
1
vote
1answer
68 views
Reading VTK file into C++ for analysis
I apologize in advance if this post is at all ignorant or elementary, I am a pure mathematician who is newly getting into the world of scientific computing.
For my research, my advisor would like me ...
1
vote
1answer
78 views
Artificial Intelligence, Modeling and Simulation
Artificial Intelligence (AI) and its subsets i.e. Deep Learning (DL), Machine Learning (ML) etc. are becoming more and more ubiquitous in engineering, technology and science. Modeling and Simulation (...
6
votes
1answer
258 views
What kind of a researcher am I?
So far, I've worked a bit in modeling, simulations and simple lab experiments, and I've really enjoyed all three research methods to approach a single research question. I can write tricky (in terms ...
0
votes
1answer
125 views
How to visualize the vorticity / flow for a rigid body moving through a fluid?
How can I write down two-dimensional Navier-Stokes equations for a simple rigid object immersed in a flow and freely falling due to gravity? I'm trying to view the vorticity that's induced by the ...
1
vote
0answers
29 views
Tackling multiscale problem in numerical simulation
In a dusty plasma system there are more than one component with different masses, i.e, electrons, ions,neutrals and dust grains. Accordingly, there are more than one temporal and spatial scales ...
3
votes
0answers
45 views
Spectral solver on em-pic
I'm recently studying for the spectral solver to implement EM-PIC code. I read an article and have some questions.
Many PIC codes uses spectral solver to overcome numerical artifacts on FDTD.
In the ...
-1
votes
1answer
52 views
How to get free energy surface of a 3d Ising Spin system using Monte Carlo simulation?
I am doing a Monte Carlo Simulation of the properties of a 3D Ising Spin system. I want to get the free energy surface of the spin system from the simulation. It is a magnetization vs free energy ...
0
votes
0answers
55 views
Stress during unloading in FEM simulation of an elasto-plastic truss element
I am simulating the behaviour of a single bar composed of two node points by fixing one point and applying a force on the oder node with $F_x = 1$ and fixing $u_y=0$. I am assuming the material to ...
2
votes
0answers
34 views
Decoupling of the fluid viscosity and incompressibility constraint in a partitioned scheme
I am new here and this is my very first question: I hope I respect all the criteria and rules.
I am just getting started with partitioned approaches for solving FSI problems. I am interested in a ...
0
votes
0answers
47 views
Why am I not getting the flat phase when Fourier-transform a Fourier-limited Gaussian pulse?
I have been trying to obtain a spectrum and a spectral phase of a Gaussian pulse using the Fast Fourier Transform provided with numpy library in Python. Here are ...
1
vote
2answers
92 views
What are the alternatives for ABAQUS in generating an *.inp file from a CAD model
ABAQUS gives a .inp file (in pre-processing stage) where the information with regard to the preprocessed model is defined, information such as geometry, mesh type, number of elements, boundary ...
1
vote
2answers
216 views
How to simulate over 1 billion particles?
I want to simulate human erythrocytes in capillaries. I calculated, that for a 1 meter long and 1 mm in diameter capillary there are about 3 billion blood cells.
Erythrocytes are actually discs, but ...
3
votes
1answer
95 views
Can one publish a new model and simulation without physical experiments?
When I read strong papers from, say, the Journal of Fluid Mechanics, a simple model, simulations and physical experimental results are given, showing good agreement.
Can one publish a new model and ...
14
votes
1answer
1k views
Conserving Energy in Physics Simulation with imperfect Numerical Solver
I am creating a C++ Physics Simulation where I need to move an rigid body through an acting force field.
Problem: simulation does not conserve energy.
Quesiton: abstractly, how is conservation of ...
2
votes
0answers
56 views
Processing time steps in chunks with Fortran [closed]
My PDE simulation program written in Fortran has to make about 2 million variable time steps. But with each time step it slows down more and more, so that if it initially makes 1000 time steps per ...
1
vote
0answers
24 views
How to simulate a PDF using data samples like this?
I know two methods to simulate a PDF from random data samples using MATLAB :
1) Using a histogram where I use this command
histogram(data,'Normalization','pdf'), it gives PDF like bins.
2) Another ...
1
vote
0answers
36 views
How to avoid density getting “deleted” in two way rigid body coupling with LBM CFD?
I've been reading this paper recently, which talks about using Lattice Boltzmann methods and two way coupling. Specifically, it outlines fluid solid coupling, and solid fluid coupling, and how simply ...
6
votes
0answers
125 views
Is a complete bacteria simulation with an exascale supercomputer possible?
Will it be possible to simulate a complete (at least simple) bacteria atom by atom on an exascale supercomputer? or is it possible already today with the largest systems?
Here, I've read that ...
1
vote
0answers
62 views
Using MATLAB to simulate the Ising Model
I am using MATLAB to simulate a 1D Ising Chain. I am running into an issue where when trying to find heat capacity, my system has a tremendous amount of noise. I'll post my code and an image of the ...
-1
votes
1answer
54 views
Smoothed Particle Hydrodynamics: Weird clustering of particles. Is that normal?
I implemented a rather simple SPH simulation using a cubic-spline-kernel and a simple non-iterative pressure solver as described in this PDF in equation 9. I followed algorithm 1 of that paper (...
12
votes
2answers
426 views
What guidelines should I follow for simulation software projects?
I am not sure whether this question belongs here, but I would like to give it a try and benefit from the experience of the people at scicomp.SE.
From my experience, the software quality in ...
3
votes
1answer
81 views
Computing autocorrelations of configurations in Monte Carlo simulations
In the context of Monte Carlo simulations, I am trying to learn how I should ensure that the configurations of my system are not correlated for the chosen interval of measurements. I have found out ...
2
votes
1answer
125 views
Why don't we call the simulation “a model for …”?
When a set of model equations, e.g. some coupled differential equations, has solutions that behave in ways similar to real-life phenomena such as blood flow in the heart, a wave movement, or a plate ...
3
votes
1answer
98 views
Calculating the Convolution Using DFT (FFT)
I have the following convolution as part of a numerical simulation.
$$T(r)=\int \mathrm{d}^3r_2\, p(r_2)f(r_2)\alpha(r-r_2)\, .$$
My problem is that the analytical expressions for $f$ and $p$ do ...
0
votes
0answers
70 views
How one can simulate a system given by differential equation?
I want to simulate a diffusion environment given by the differential equation
$$\frac{\partial u(x,y,t)}{\partial t}=D\left(\frac{\partial^2 u(x,y,t)}{\partial x^2}+\frac{\partial^2 u(x,y,t)}{\...
2
votes
0answers
40 views
What is the best methodology for physics simulators of large floating base rigid body systems?
I want to implement a physics simulator for large floating base rigid body systems from scratch. The Rigid Body Dynamics Systems (RBD) should typically have the following characteristics:
About ~50 ...
0
votes
0answers
48 views
Simulate friction arround steady-state point
When simulating a friction dynamic system, I have come to a problem when approaching steady-state.
In the example below, a box moves along a surface with a certain friction coefficient:
...
2
votes
1answer
70 views
Plasma Simulation Software Advice?
I’m looking for software that can simulate “hot” plasmas of multiple ion species...so some sort of simulation software that could calculate ion temperature and density distributions taking into ...
0
votes
1answer
34 views
How to implement the Impulse Based Dynamics for the rigid body dynamics simulation?
I am having hard time learning the method of impulse based dynamics developed by Mirtich for rigid body dynamics simulation. Please help me out if any body has any example code(algorithm) of it. ...
2
votes
1answer
82 views
Symplectic linear multistep method?
I'm doing a gravitational n-body simulator and I'm thinking of implementing linear multistep methods like Adam-Bashforth. But is there any symplectic multistep methods?
5
votes
2answers
123 views
Is saying “math modeling and numerical simulation” wordy and redundant?
I'm describing some work on my website, and I'm wondering if my math modeling and computer simulation work is described ok: I say
math modeling and numerical simulation.
Should I say "...
3
votes
2answers
103 views
Optimization techniques for expensive multi-variable functions
I'm working with a finite element model in which I'm interested to minimize the average temperature at a surface. I have 15 independent variables in my model, including geometry, materials, flows, ...
1
vote
1answer
57 views
Harmonic oscillators with periodic boundary conditions
I am trying to simulate multiple harmonic oscillators in periodic boundary conditions (subsequently visualizing the process in VMD). I have successfully simulated multiple HOs by using the Leapfrog ...
1
vote
1answer
176 views
Can OpenFoam be used for interactive simulations (flying a plane)?
I'm a software engineer and I've just started to fly rc-planes. I'm currently building a self learning auto-pilot for my plane and I'm really interested in CFD. I installed OpenFOAM and ran through ...
1
vote
1answer
46 views
How to choose the parameters for a collision free comet trajectory
I implemented a simple simulation of a comet flying through space being deflected by the gravity of randomly generated planets for art purposes. My problem with that simulation is, that there are many ...
0
votes
1answer
32 views
Software for cellular automota
I would like to do simulations using cellular automata to describe the behavior of influenza. What software do you recommend?
0
votes
1answer
66 views
Simulating Brownian motion in 3-D for first hitting time?
I want to simulate Brownian motion in 3-D for the following conditions:
$$p(x=0,y=0,z=0,t=0)=1$$
$$p(x,y,z=c,t)=0$$ where $p$ is the probability of finding molecules in the 3-D environment. I want to ...
3
votes
1answer
69 views
Radiation heat transfer between surfaces
I'm trying to model the temperature distribution over a curved surface. Apart from the heat equation, I need to take into account the energy emission/absorption through electromagnetic radiation. The ...
-1
votes
1answer
70 views
Writing parallel code for molecular computation [duplicate]
I recently moved towards computational biophysics from an experimental science background. As of now, I am learning the fundamentals and doing some basic monte carlo simulations of LJ fluid on my ...
1
vote
2answers
141 views
Custom exponents for Lennard Jones in LAMMPS
I am trying to run an MD simulation using this generalized version of Lennard Jones.
$$
U(r) = \left(\frac{r_0}{r}\right)^A -\frac{A}{B}\left( \frac{r_0}{r} \right)^B
$$
However, I do not know how ...
3
votes
2answers
868 views
How to simulate basic semiconductor models using the Drift-diffusion model on Python?
I'm trying to simulate basic semiconductor models for pedagogical purposes--starting from the Drift-diffusion model. Although I don't want to use an off-the-shelf semiconductor simulator--I'll be ...
1
vote
1answer
88 views
Multi-steps method for Navier-stokes equations with strongly nonlinear diffusion
I am trying to solve a particular form of the Euler / Navier-Stokes equations in 1D, with very strong and non-linear diffusion coefficients.
My system of equations is
\begin{cases}
\...
