What is Simulation: Definition and 885 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. andrenepomuceno

    JavaScript Particle.js: Exploring Particle Physics with Web Technologies

    Hello everyone! I am excited to share my latest project, Particle.js, a simplified N-body particle physics simulation designed as an educational and experimental tool. This project is not intended to be a precise scientific instrument but rather a way for enthusiasts and learners to visualize...
  2. G

    Help Needed with MCNP Simulation for Brachytherapy Treatment Room

    Hello everyone, I am currently working on a Monte Carlo N-Particle (MCNP) simulation and have encountered several issues that I hope someone here can help me resolve. My project involves simulating a brachytherapy treatment room, and I am struggling with defining the cells, surfaces, and...
  3. R

    MCNP Burnup Calculation

    Hi everyone, I'm a newbie to MCNP, I'm trying to calculate burnup for this pellet I include here in a PWR in an infinitely repeated geometry, but it seems to be failing for some reason. I get the error message: ctm = 0.00 nrn = 0 dump 1 on file runtpp.h5 nps =...
  4. Haia

    Rsoft BeamProp software - redeem my misery!

    Hi everyone!:) I'm Having a rough time with Rsoft BeamProp simulation software, I am simulating an multi-core fiber with my own specific design and am trying to divide the fiber into regions (in z axis) - the software would only let me divide a specific core (and more specifically the middle...
  5. fahadismath

    Rate equation for fluid flow

    does anyone know the derivation of the general solution of the nonhomogeneous equation shown in the image (book name: Devendra K. Chaturvedi - Modeling and Simulation of Systems Using MATLAB and Simulink -CRC Press (2010))
  6. A

    Ltspice - divided two plots from different run simulations

    Hi, I have a plot of v(onoise) of my circle using noise simulation. I also have my V(output) from my ac frequency analysis. How do i divide between the graphs?
  7. steph_ws23

    Learning VisEd for MCNP

    I'm beginning in Vised for MCNP6 and i want to modify my imput file inside vised to understand how when i changed cards this affects the simulation. The problem is that i can't save inside vised my imput file, i have to open my imput file in an editor text an then reopen this file in vised...
  8. F

    Simulation of load-unload test in Abaqus

    Hello, I am trying to simulate the load-unload test in Abaqus under the following loading schedule using my UMAT (which has already been validated). As you see, the load-unload test is pure tensile with positive displacements; however as I modelled it in Abaqus the force-displacement curve as...
  9. frhnsaif

    Radioisotope Decay Simulation in MCNP6

    Hi all I am a new user of MCNP.I want to simulate radioactive decay of Bi-213 (whole decay chain till stable element) in two concentric spheres of water (let say 5um and 10 um).I want to calculate energy deposited in big sphere(10um) if source is distributed in inner sphere(5 um) .What physics...
  10. M

    Simulation of Cyclic Loading in Tensile Test

    I am currently working on a FE simulation project where a tensile test of DP800 steel is subjected to cyclic loading. It utilizes Yoshida Uemori model (YUM) to formulate the modulus of elasticity (E) to simulate the hysteresis caused by cyclic loading. We are using a USDFLD subroutine in...
  11. Aidoush

    Looking for help in simulation moving mesh case

    I was looking for a respond on moving mesh using COMSOL, while I was searching on Google I found a response in your forum.
  12. Marina123456

    To simulate the interaction of gamma photons with only oxygen (O) atom

    Hello! i need help in such case. I want to simulate the interaction of gamma photons with only oxygen (O) atoms in MCNP, while am using the material card for silicon dioxide (SiO2). Which card shall I use to get the photon interacted with only the oxygen component separately. Thanks for help.
  13. A

    Airbag Simulation using LS-DYNA: start from filled airbag

    Hello! I'd like to model the impact of an object on an inflated air cushion (effectively an airbag) at rest in LS-DYNA, however all the tutorials I see start from a deflated airbag. I would like to skip this computation if possible to save computing time, since I would have to run the simulation...
  14. K

    A Noise in Landau–Zener transition

    Hello! I want to simulate a 2 level system in which the 2 levels are connected by an off-diagonal Hamiltonian term. I can linearly tune the distance between the 2 levels and thus I can transfer population from one to the other using a Landau–Zener transition. However, I want to add noise to this...
  15. Y

    Axial flux motor core loss model simulation

    Hello, I'm a student, working on project related to electric motor. Currently I'm trying to simulate a 350W power axial flux motor on Ansys Maxwell 3D. Until now I have been able to get BEMF of motor, further I'm trying to find losses in motor like core losses & copper losses. The core loss data...
  16. Kahraman

    Ansys Maxwell Simulation - Torque Fluctuating

    Hello everyone I simulated the eddy current brake of 2 1000-turn coils with 5 amp excitation in Ansys Maxwell, but the torque fluctuates. How can I overcome this problem? If you want to see it in more detail, you can download the project from the link. "" (Sorry for any language errors)
  17. S

    B How long is the start up time for a simulation of the solar system's formation?

    Was reading about a simulation and there isn't any mention about what amount of time it takes to start and to run. Since they're potentially on a supercomputer, maybe not a long time. I have no idea what to expect though. Do you sit at it like a regular desktop and press play, then it starts...
  18. G

    Simulated voltage gain in Multisim differs very much from calculated

    I am using Multisim software and I am comparing my calculated voltage gain with the one, done by Multisim. Why is calculated Av ( -478.8 mV) much different from the one in simulation ( -990 mV) ? I see the calculated is approx. half size of simulated. I tried using virtual transistor instead...
  19. SacCno

    B Help Scaling Gravity Simulation

    I'm trying to make a 2D game on Unity similar to Universe Sandbox 2. I currently am working with a star and planet, both with roughly the masses of the sun and earth respectively for comparison and at a distance of 31,000,000km. My current model uses Newton's formula for gravitational force (F...
  20. Phys pilot

    Best software to simulate the radiation emitted by uranium powder inside a pipe?

    Hello, I need to carry some simulations for my master's project and my tutor doesn't know much about simulations. I can't tell much since it is related with a private company but basically I'll have to simulate and measure the radiation emitted by some enriched uranium particles or uranium...
  21. gibatom

    Simulation of a gas in 2-D using a Verlet algorithm

    Verlet Algorithm with periodic conditions
  22. M

    FLUKA: Why Does Neutron Flux Increase When Passing Through a Moderator?

    I have been banging my head against this for a few weeks now; tweaking the simulation, adjusting my calculations, and searching around the web to try to find an answer. I can't post questions on CERN's Fluka help forum so this seemed like the best option. I really appreciate any help you can...
  23. L

    Engineering Show a resonant curve in a simulation between 800hz and 4.5khz

    i have created the circuit but i am not sure what to do from here, this program is new to me
  24. gxa

    Background Analysis for MCBEND Simulation

    I have compared my simulation results with the experiments I conducted in the laboratory. Here I want to add a background for the graph I obtained from the simulation. Can I do it? I would be very happy if you could help me. I used MCBEND as the simulation program.
  25. L

    Comp Sci Use a simulator to produce a resonance curve for this RLC circuit

    my issue here is what would i put in for frequency ? unless i use the formula to find the resonance frequency i have only used multisim live and you cant put in Vs 10 +j20
  26. L

    Engineering Create a circuit in simulation to prove my work (2 batteries and 1 lamp bulb)

    so this is a question i am trying to solve and then confirm with the simulation, so far i have.. Lamp load IL = PL/VL 1/6 = 0.1667A Thevenin resistance Rth = Rs1 || Rs 2 = 2 x 4 / 2 +4 = 1.333ohms Vth = 12V look at node voltage with load circuit and use kcl V = 6V Is1 = 12 -6 / 2 = 3A Is2 =...
  27. PhysicsTest

    PWM sweep from 0 - 100% duty cycle in LTSpice

    How do i simulate the PWM signal with duty from 0% to 100% in Ltspice. I can generate a pwm signal with single duty.
  28. gxa

    Real Experiment-MCBEND Simulation

    Do I need to apply normalization these two graphs to make them similar to each other and if so, how can I do this? I would be very grateful if you can help me if these results are consistent. I compared the results of the experiment and the results of the mcbend simulation.
  29. H

    How Can I Simulate Induced EMF in a Coil Using Ansys Maxwell?

    Hi guys, I'm new to this forum. I'd like to know how I could perform a simulation to find the induced EMF in a coil placed closer to a current-carrying conductor. I'm not sure how I should model the coil. I tried modelling it as a solenoid but the solenoid exceeds my required length when I enter...
  30. S

    Improve Result of my CFD results

    Im running a CFD simulation. Looking at improve my CFD simulation. my mesh is currently low density. Q) Would increasing mesh density around the boundaries of the air craft wing capture the forces (velcoty & pressure) on my velocity map and added streamlines.
  31. F

    Monte Carlo Simulation vs ML Models

    Hello, I have become familiar with ML and a number of ML models (supervised and unsupervised). I would like to now learn about Monte Carlo simulations since they are so ubiquitous in many fields. When would we choose to do a Monte Carlo simulation instead of building a ML model (supervised...
  32. N

    Creating FMESH Tally Over Region - Troubleshooting

    I am trying to create a FMESH tally over a region that's (x: -15um to 15um, y:-15um to 15um, z:10um to 60um). My input code is below: FC4 FMESH tally energy deposition FMESH4:E GEOM=xyz ORIGIN= -0.0015 -0.0015 0.0010 & IMESH=0.0015 IINTS=10 & JMESH=0.0015 JINTS=1 &...
  33. N

    Why am I seeing a discrepancy in photon energy when doping ZnS:Ag in MCNP 6.1?

    I am a new user of MCNP and I am trying to generate photons in ZnS:Ag through electrons as my source particle. My simulation as it is now creates photons however they are not right. For example ZnS:Ag should create a lot of photons with energy of around 3.1eV. However I see a spike around 4.8eV...
  34. Amsalja

    What is Velocity.length_squared?

    I'm not sure. A source said New Velocity = Current Velocity - TerminalVelocity every second until New Velocity = TerminalVelocity But it doesn't seem right
  35. Z

    What Can You Learn About Engineering on PhysicsForums?

    Hello I'm Mike. I'm a Mech Simulation Engineer. I am grateful with the help from this forum which directly solve my problem. Hope I can gain more engineering knowledge and experience, and also can help others. Best regards!
  36. Chimaera987

    Inertia of the drivetrain components of a 4x4 vehicle

    Hi, 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 = engine_Inertia; this should contain the inertia of the engine and all of it’s auxiliaries...
  37. S

    Engineering Solve Inaccurate CFD Predictions: Improve Results

    Hi Im confused with what the CFD Results show or mean. I have never done CFD before and don’t have any material explaining it. Question Find areas of potential inaccurate predictions in the simulation and improvments. This is the instructions I had to follow...
  38. Engineer_Kosyakova

    COMSOL: Simulation of liquid nitrogen cooling (Help please)

    The InSb sample (parameters 10x10x0.5 mm) is glued with silver glue to a cooled copper table. Liquid nitrogen passes through the table. While the model is at a temperature of 300 K and at a normal pressure of 1 bar. The sample is affected by a beam of electrons, which causes the surface to heat...
  39. E

    I Research paper and sources investigating Earth's moons

    Hi. I am looking for scientific papers, articles and/or even simulations that investigate how many moons it would be possible for earth to have and maybe modern theories about what these moons can be and look like (i.e what characteristics they have) if they were to exist. I have googled and...
  40. Astronuc

    Modeling and Simulation in Nuclear Energy

    Modeling and simulation, or computational physics/chemistry, is a large and important part of engineering. In nuclear energy, there are applications of finite element methods (and occasionally finite different or finite volume depending on the problem) applied to nuclear plants, nuclear...
  41. physicsclaus

    Sending drive Pulse in CQED and visualize the state by QuTip

    [Mentor Note -- This thread is a continuation of a previous thread, with the emphasis in this new thread on the programming implementation. Previous thread is here: https://www.physicsforums.com/threads/can-anyone-give-me-the-details-of-creating-a-cat-state-in-circuit-qed.1048821/ ] Hello...
  42. Jessie24789

    I Doppler Shift & Christoffel Symbols Issues

    About a month or two ago I started doing simulations of light physics around black holes and yesterday I got a fast Christoffel symbols function for the Schwarzschild metric in cartesian coordinates, but now the photon ring appears flipped. I feel as though it is wrong. But as I am still pretty...
  43. R

    I I made an N-body simulation program

    My little project - 3body simulator started as a programming exercise, which I attempted to make a program that solves the famous 3-body gravity problem using numerical integration. Later I gained interest in the underlying physics and expanded the program to solve N-body problems involving...
  44. FEAnalyst

    Triangular cavity thermal radiation simulation

    Hi, I'm trying to solve a problem involving radiation in a triangular cavity: As you can see, lengths and emissivities of all surfaces are given. For two of them, the heat flux is known and the temperature has to be found while for the remaining surface it's the other way around. I have the...
  45. S

    Automotive Amplitude based frequency response simulation in Abaqus

    Hi, I have inputs like displacement of a driving mechanism and then the frequency of concern . Displacement: 0.2 mm Concerned Frequency: 100 Hz I would like to evaluate a part with the input displacement applied to a node and not as base excitation. It can be sweep over the frequency range...
  46. shivajikobardan

    MHB What is the difference between activity and event in "simulation"?

    I am studying about components of a system. Activity-: It is What entities do to cause changes is activity. It is represented by time period of a specified length. Event-: Event is defined as an instantaneous occurrence that might change state of the system. Endogenous events occurs within...
  47. TheJP78

    Python Building a Solar System simulation with python

    Hey'all. First of all, I'm not fluent in English, so forgive me for the spelling mistakes. So, I'm trying to make a simulation of a solar system using python 3.9. It's not complicated, but my teacher wants me to do it using the Basic Verlet method, and that's what is bugging me. He told me do do...
  48. T

    I Why Does J*T Show Band-Like Behavior with Particle Spacing?

    Hey All, The simulation I am currently looking at is regarding the following paper: https://iopscience.iop.org/article/10.1088/1367-2630/10/4/045030. Let us define J = C_{3}/R^{3} (equation (2) in the paper) and let T be the simulation time until the trajectories of each particle changes by at...
  49. tysonman166

    MCNP6 simulation still running but no change for a while

    After previous thread my program finally work and i could get the Keff final. But problem rises when MCNP want to do "predictor" and "corrector". I already wait for 3 hours but there is no update for the corrector (screenshot attached). heres the profof that my program still running: and in...
  50. Hasan2022

    COMSOL simulation of a 3D Ferrite Bar Numerical Model For Magnetic Flux

    Hi, I am willing to simulate a 3D ferrite bar transmitter and reciever where coupling coefficient k and Bt magnetic flux density on the each side uses the finite element method for solving partial differential equations. The Magnetic Fields module has equation (jωσ − ω2ε0εr)A + ∇ × H = Je...