Simulation Definition and 119 Discussions

A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Often, computers are used to execute the simulation.
Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. Simulation is also used with scientific modelling of natural systems or human systems to gain insight into their functioning, as in economics. Simulation can be used to show the eventual real effects of alternative conditions and courses of action. Simulation is also used when the real system cannot be engaged, because it may not be accessible, or it may be dangerous or unacceptable to engage, or it is being designed but not yet built, or it may simply not exist.Key issues in modeling and simulation include the acquisition of valid sources of information about the relevant selection of key characteristics and behaviors used to build the model, the use of simplifying approximations and assumptions within the model, and fidelity and validity of the simulation outcomes. Procedures and protocols for model verification and validation are an ongoing field of academic study, refinement, research and development in simulations technology or practice, particularly in the work of computer simulation.

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1. I Relative Strength of the Magnus effect relative to gravity

I have made a simulation of a table tennis ball being hit and landing on the table. There are 5 differential equations that are integrated to compute the horizontal position, horizontal velocity, vertical position, vertical speed and spin. by integrating 5 differential equations simultaneously...
2. A What is meant by pruning and enrichment?

As far as I understand: Pruning means deleting something. Enrich means to enhance/increase weight. Now my question is, in the case of the PERM algorithm, Are we deleting some polymers chains? Or, are we deleting some beads in all polymer chains? Are we increasing the weights of some...
3. Common mode current simulation

Hello! I'm trying to model common mode current with LTSpice, but there is a problem with my simulation. Someone else tried on an other software and got the expected result, but I can't explain why. When going through the capacitor, square signals should become pulses, but that's not the case...
4. COMSOL: stress on a sensor, how to use infinite element domain?

At the risk of waiting hours on simulations of a sensor, I was wondering if I could use infinite element domain on COMSOL to simplify it. The first image consists of what I would like to simulate but found out that the simulation time is a huge factor as I have a lot to simulations to conduct...
5. Ansys Maxwell: Transient generator simulation torque fluctuation

I am working on an axial flux generator design, I consisits of 2 rotors and one stator, there are 6 pole pairs and 9 coils. Here is my simulation setup The three phase windings are connected in star configuration through Maxwell circuit. I created two bands enclosing each rotor and then united...
6. I Centrifugal Effects During Rail Launch

I’m writing a 3DOF sim for a rocket. I’m having a hard time visualizing centrifugal effects from the earths rotation on the rocket while it is moving along the rail (acceleration > 0). I know that once it has left the rail I no longer need to account for it since it’s in the ECI frame and...
7. A Thermal shock wave question from my hydrodynamics simulation

This is a fluid dynamic simulation. The top area has 100 degrees Celsius. The bottom area has 0 degrees Celsius. And both are filled with an ideal gas which is 1-atmosphere pressure. Two areas are connected through the left small line. Another part is blocked. So heat transfer can only happen...
8. Automotive Need assistance in Abaqus simulation

I'm doing static analysis. I have already set up all the prerequisites, preprocessors such as material addition, sectioning, defining boundary conditions, and displacement. However, I'm not getting the results. Please suggest anything. Kindly find the attachment. regards
9. A All-atom simulation and coarse-grained simulations

I am currently reading this [paper by Noid et. al.](https://doi.org/10.1063/1.2938860) on the rigorous bridge between atomistic and coarse-grained simulations. In the paper, he defined a linear map from the atomistic coordinates and momenta $$\mathbf{r}^n, \mathbf{p}^n$$ to the coarse-grained...
10. I The Simulation Theory and the dangers of pop-science

. I should preface by saying I'm a geologist not a physicist... Gotta say I usually avoid people who talk about the simulation stuff but I just saw a Tedx by George Smoot and it wound me up... Anyway, the simulation hypothesis seems to me, and most other scientists to basically be a bit of a...
11. MATLAB More Efficient Way of Computing Neighbors in Range

Hi. I have a collection of points in 3D space. I'm using MATLAB to find all pairs of points within a certain range from one another. Right now I'm using rangesearch(X,X,r), where X is the collection of points and r is the range. These points are the locations of atoms and I am attempting to...
12. Best Environment/Programming Language for simple physics Simulations

Hello, I am looking for something to simulate/visualize simple particles and classical physics equations, preferably moving in real time Requirements: -Able to turn matrices/functions into geometric representations(visualize sphere, visualize a cylinder etc.) -Can do the classic ball bouncing...
13. Comp Sci Galaxy simulation with the velocity Verlet algorithm

To simulate the trayectories of solar systems around a blackhole (i.e. a galaxy) I have 3 classes in C++: cSystem, cBlackHole and cGalaxy. cSystem assigns initial values of position, velocity, etc to a solar system. cBlackHole does the same but just for the black hole. And cGalaxy mixes...
14. Virtual Physics Labs - giving some resources and asking for some

Hi all! Like everyone else, our university physics department is prepping for online labs. We are utilizing great simulations from several sites, check them out below if you haven't already. We are able to rewrite many of our labs 1:1 conversion to online! Colorado PhETs...of course ...
15. How can I create an equation in matlab for image processing?

Here is the documentation for the 2DFFT: https://www.mathworks.com/help/matlab/ref/fft2.html how would I go about creating this formula on matlab to apply it on an image? My guess is that I need to create the equation and then multiply it to the image I need such as: $$U = VI$$ where V is my...
16. Line filter, proper LTspice simulation

Dear forumers, I have two high performance AC feedthrough capacitors (47nF, 100A, class Y2, DC-60Hz) which I want to either combine with a general purpose EMC line filter, or build a custom one to filter the mains from of about 100khz to as high as possible (for shielding purposes). I can see...
17. Thermodynamics: calculate thermodynamic derivative from data?

I don't understand how to use output from an NPT molecular dynamics simulation to compute a thermodynamic derivative. I need to compute this (where "d" is a partial derivative, "T" is a subscript that means, "at constant temperature," and "E" is internal energy): -(dE/dV)T I have a simulation...
18. Modeling/Analysis of optical fibers

Hello PF, I need some guide points to help me formulate a project idea on the topic of optical fibers. Namely, the professor suggested I should look for topics on modeling of optical fibers, analysis of different optical fibers, characteristics etc. and to work in a simulator, or perform a...
19. How can I make a simple inductive MHD thruster in water simulation?

Homework Statement:: Simualte the behaviour of water around an mhd inductive thruster Relevant Equations:: https://www.comsol.fr/paper/download/45837/Pintus.pdf Where can I start this simulation ? What is the required software ? [Mentor Note -- thread moved from the technical forums]
20. Velocity change under drag and other forces: small mass, large delta-t

I am working on simulating the movement of small spherical objects under the influence of drag and a number of other forces that, at least for now, don't depend on the object's velocity. Normally I would sum up all these forces, including drag, to ##F_\Sigma## and update the object's speed...
21. The simulation of a microwave antenna made of nanofilm Ti3C2 (Mxene)

Hello! I am a student of the radio engineering faculty and now I am engaged in master's work. The purpose of my work is to find application for Ti3C2 in antenna technology. I found a lot of information from article http://advances.sciencemag.org/content/4/9/eaau0920 But I can't understand how...
22. Free circuit simulation software/website for beginners

I was looking for simulation softwares that are free. I looked at some on the net, but they aren't satisfying my basic requirements. A simulation software should at least have the following for my use: Arduino support Support for buck converter Solid state relay Transformer Variable AC supply...
23. A (a,n) Reaction Simulation

Hi, Can someone suggest me an open source code for simulation of (a,n) reactions? I want to build a geometry(sphere) with an a-decay radioisotope covered by Beryllium and count the neutron production. Thanks a lot
24. A Dissociative ionization Monte Carlo simulations

Hi, i'm wondering if there any exists a Monte Carlo free code that can simulate dissociative ionization, per example a beam of protons on water, and then track the fragments (from water) and their energy. Thanks in advance!
25. A What is best way to start learning DMRG for Fermions?

I want to learn the density matrix renormalization group (DMRG) method in traditional formalism (not MPS). While there are many good introductory level articles available for bosonic (and spin) systems, I have not encountered any introductory level article which deals with fermionic systems i.e...
26. A How to numerically diagonalize a Hamiltonian in a subspace?

I want to exactly diagonalize the following Hamiltonian for ##10## number of sites and ##5## number of spinless fermions $$H = -t\sum_i^{L-1} \big[c_i^\dagger c_{i+1} - c_i c_{i+1}^\dagger\big] + V\sum_i^{L-1} n_i n_{i+1}$$ here ##L## is total number of sites, creation (##c^\dagger##) and...
27. Using a normal processors for HPC

Hello all: Can you use current of shelf multicore PC as a high performance computer Can it handle the job ? Dose the outcome data tables and simulation results , is correct and with low error margins With out gpu like cuda or opencl Best Hagop
28. A Lagrangian vs pseudo-Lagrangian vs Eulerian

I'm reading up a series of papers on hydrodynamical simulations for galaxies and cosmology. They keep mentioning things like "Lagrangian" or "pseudo-lagrangian" or "Eulerian". I tried looking it up on the internet, but the answers are either too broad and could mean a huge number of things in...
29. Defining a BH loop in Ansys Maxwell?

Does anyone have an idea how to insert a BH loop like the one I have attached in Ansys Maxwell and not get an error like in the other picture which is also attached? I have seen it multiple times in different texts but can't define one myself without getting this annoying error. Also the...
30. A LQG Simulation

Hello, I am contacting you because I would like to know if there is a way to simulate quantum loop theory. Indeed, the S-Knots are much more complex objects than graphs because between the points there is a curve that can be knotted. S-Knots are graph embeddings in 3D and I do not see how such...
31. How to define a hysteresis loop in ANSYS MAXWELL?

I am trying to simulate an electric motor in ansys maxwell software, but I can't define the whole loop in four quadrants for the material used in the rotor however it is essential to do this since the motor is of hysteresis type and works on the principle of working point moving all around the...
32. I Planetary accretion model?

Hi - having come up blank when searching, I figured I'd ask here: do you know of any (free, preferably open source) planetary accretion models/simulators available for download? I'm primarily looking for solar system formation / evolution rather than planetary geochemistry (although I'd have an...
33. MATLAB Switched from win10 and MATLAB to ubuntu and python"q"

Hi, I felt like I have to learn more than one coding language, and wanted to strengthen my coding skills in general. I am good with Relap5 but I want to learn OpenFoam. is what I did logical and going to be worth the pain ? also I only have the Relap5 version of a windows ,is it possible to run...
34. A Simulation from a process given by "complicated" SDE

Actually this is more of a simulation question but since PF doesn't have Simulation category I ask here. I need to simulate a path from a proces given by this Stochastic DE: $$dX_t = -a(X_t-1)dt+b\sqrt{X_t}dB_t$$ where ##B_t## is wiener process/brownian motion and a and b are just some...
35. MCNP source definition question

I'm modelling a scenario for the research that I'm working on, and I got the cells and surfaces all mapped out for the environment finally, but now I'm totally stuck on creating a source. I'd like a point source of Californium-252, but after hours of looking, I don't see any out of the 1000...

Hi guys, I'm wanting to simulate faraday cage form, analysing mesh perforations defined by wavelengths of different electromagnetic spectra (eg. radio, microwave, UV etc). Are there any good analysis softwares which I could import a pre-made digital model with these perforations and simulate...
37. Universe is a Simulation

Now, we all know all physical things are related to math. EVERYTHING is related to math. Now, we have all heard the theory that we are all living in a simulation, right? What if... math is the coding of the simulation and throughout time we have been decoding our own simulation.
38. Recommended physics engine?

Hello! I'm trying to write a 2D program that uses simple physics. I was wondering what would be the best 2D physics engine to use in my case, and if it even matter what engine I choose. I also want my simulation to run in real time, so at least 30 fps on a decent home computer. I prefer a fast...
39. Need tutorial for magneto static simulation of C-core (Imag)

Hello all, I am a new member of this forum, I would like to know where can i find the detailed tutorial of magneto static simulation of C-core. I am in the middle of one project and for further move I need the magneto static simulation of C-core. The image is attached.
40. New Life History Simulation Modeling Platform

mod: approved HexSim Life History Simulation Modeling Platform - free to download. Landscape ecology, anyone? After >10 years of development, the HexSim life history simulator is ready for use by students and researchers.HexSim is a free, versatile, multi-species, life history simulator ideal...
41. Simulation with COMSOL - uniform pressure

Hi, anyone using COMSOL? I'm new to this program and I'm trying to get a plot of the pressure distribution on a cut-plane of a cube. I have applied a boundary load of 4 MPa to the upper surface of the cube and fixed constraint to the bottom surface of the cube. Now, as a check, when plotting...
42. I What is the propagation speed of a diffusion

Hello everybody! For my water in nanoscaled-pores simulations with SPH I need a value for the characteristic velocity. My planned approach is to estimate this value by attaining the propagation speed of a diffusion wave. But I have problems with understanding this process since I find some...
43. What is the final velocity of a ball rolling through a tube?

I am making a physics simulator and this problem is tricky. You have two freely moving objects with known masses and velocities in a frictionless environment. The first object is a ball and the second is a pipe. They are moving toward each other. I need to know what formulas are used to simulate...
44. A General relativity package for Friedman equations

I need to simulate the Friedman equations under different conditions of flat space. Can someone please tell me a good package in MATLAB, Mathematica or stand alone. I am most well versed in MATLAB but have coded in Mathematica before.
45. Ansys Workbench Fracture and Cracking Behavior using Solid65

I am trying to simulate concrete material under three-point bending in Ansys Workbench 16.0. The concrete beam (unnotched) will be under displacement load at the center while as the both ends will be fixed. The design geometry is simple which I have already completed. I ran the simulation using...
46. Modeling analytical solution of 1D heat equation

I am trying to write code for analytical solution of 1D heat conduction equation in semi-infinite rod. The analytical solution is given by Carslaw and Jaeger 1959 (p305) as $$h(x,t) = \Delta H .erfc( \frac{x}{2 \sqrt[]{vt} } )$$ where x is distance, v is diffusivity (material property) and t...
47. I How to determine if an asteroid will burn up or hit Earth?

I want to make a interactive simulation that shows whether or not an asteroid will hit the surface of the Earth. It would have 2 sliders for you to control the speed and mass of the asteroid. The simulation will output "yes" or "no" if the asteroid hits the surface. Is there a mathematical...
48. Performing Metropolis-Hastings algorithm for a Poisson Distribution

Homework Statement The number of busy lines in a trunk group (Erlang system) is given by a truncated Poisson distribution. I am asked to generate values from this distribution by applying the Metropolis-Hastings algorithm. Homework Equations The distribution is given in the attached picture...
49. Heat transfer into a sphere

Hi, I am looking to simulate a very - seemingly - simple case. Any advice on a software package would be helpful - preferably gui which doesnt have a steep learning curve. I want to model the heat flux into a sphere from the outside. The dimensions of the sphere are not important to me. I...
50. C/++/# Velocity Verlet C++ implementation

I have been working on implementing a solar system system simulator in C++ - but am getting incorrect results on the order of 10^10 km, and it seems that the planets are moving directly away from the sun. I suspect that there is a mistake in the integrator (Velocity Verlet) that I have posted...