# Questions tagged [simulation]

Simulation is the process of mimicking the behaviour of a real physical process or system using a representative model.

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### Determining Stainless Steel Pipe Length for Heat Transfer to Reach 1000°C

I'm working on a Uni project where I need to determine the length of a stainless steel pipe that is required to heat a fluid up to 1000°C. The pipe will be placed in an oven that can reach up to 1400°...
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### How do we calculate solvent accessible surface area (SASA) for a system simulated with annealing protocols in Gromacs?

I calculated SASA for 4 systems using the following command. The trajectory file (run.xtc) is not treated with gmx trjconv option. In my MD simulation, I followed two annealing cycles in each 50 ns ...
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### Simulating a dataset from model output when model includes multiple binary deviation-coded variables

I am trying to simulate data using parameters from a glmer() model output. The model, which comes from a published paper, is as follows: DV ~ 1 + group* sex *verb type + trial number + (1 |participant)...
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### Softening vs Smoothing Length... Is There a Difference?

I have a simple questions on terminology. Is there a difference between softening length and smoothing length? I have been using the 2 terms interchangeably as the minimum distance between particles ...
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1 vote
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### Why does a two-body simulation result in no change of the y-component?

I've been attempting to create a model of a heliocentric orbit based on Newton's law of gravitation: $$\frac{d^2 \vec r}{dt^2} = -\frac{GM}{|r|^2} \hat r$$ This is what I have so far: ...
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1 vote
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### Calculating Madelung constant via Ewald summation

I am attempting to calculate the Madelung constant for NaCl using an Ewald sum derived by Nijboer. There are other methods and published codes to do this, but I am specifically interested in working ...
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### Starting configuration for Molecular Dynamics

I have to build a bilayer using a structure obtained in a previous MD simulation. In the structure, some chains of the molecules cross the simulation box as shown below. I added water layers to the ...
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### In electromagnetic simulation, how much does the feed model impact an antenna's directivity performance and E-field phase readings?

Question: How much would a simplified feed model in an EM simulation alter an antenna's directivity and the E-field phase reading when compared to using a more complicated/realistic feed model? I am ...
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### Modeling Homeostatic Regulation with Python: How to Simulate Dynamic Systems

Hello Computational Science community, I am working on modeling a dynamic system that involves homeostatic regulation in Python and I could use some guidance on how to implement it. Here's a brief ...
155 views

### Damping not working in Verlet simulation with absolute constraint

I'm trying to build a simple physic simulation with Verlet intergration, which I'm currently implementing as such: ...
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### Deformation matrix, Math hack for stability on large simulation steps?

So there is a numeric technique for updating a deformation gradient in MPM that goes as: $$F_{n+1} = (I + \nabla \vec v \Delta t)F_n$$ This works for small time steps but for large time steps ...
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1 vote
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### Improved euler on hybrid methods where both time and space are discretized?

I am trying to understand how to use the improved euler method on MPM simulations. In the kind of MPM simulation I am doing with forward euler the order of operations is as follows: Write particle ...
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### Verlet integration on grids or how to get better stability in hyperelastic simulation

I am using MLS-MPM to simulate both solid and fluids. It works, but the amount of time steps I must do for hyperelastic solids is absurd. To give you some perspective, I am able to simulate just the ...
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### Professional orbital simulation software methods, accuracy, runtime

I'm working on an orbital body simulation as a personal project. I understand that it's not going to be as good as professional software, but I'm wondering what contemporary, general purpose, ...
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### How to calculate the change in water level height after each step in a water displacement simulation?

I'm trying to write a very simple simulation of volume/water displacement. Every timestep a sphere gets lowered a bit further into a cylindrical container filled with water. While the physics behind ...
1 vote
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### Monte Carlo simulation of classical Heisenberg model doesn't represent Curie curve

I've created a JavaScript file to execute and log average energy and magnetization values of 2D lattice classical Heisenberg model. I run the simulation with parameters, ...
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### I encountered some issues simulating the shape transition of silicon clusters using LAMMPS

== I have been trying to write an input file for lammps to simulate the shape transition of a nanoparticle of silicon using multiple potentials to obtain the best structure, which I will compare with ...
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### Energy potential involvign pressure and viscoscity?

Making a really long explanation short. I am looking for an energy density function for an incompressible isotropic fluid that involves both viscoscity and pressure. The reason is, there is a way to ...
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### Why not use the convolution theorem for explicit timestepping?

Consider the advection equation $$\frac{\partial C}{\partial t} + u\frac{\partial C}{\partial x} + v\frac{\partial C}{\partial y} = 0$$ I want to do a forward time, center ...
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### Beam propogation method for a waveguide. How to get single mode?

I am simulating a waveguide using diffractio python library (https://diffractio.readthedocs.io/en/latest/readme.html). The idea is to create a single mode waveguide using wave propogation method. ...
179 views

### How to implement large rotations in total lagrangian formulation (nonlinear FEM)?

I have developed an Octave script to solve the nonlinear Euler-Bernoulli beam equations with linearized von Karman-strains, i.e. higher-order terms are dropped. The simulation results agree with ...
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1 vote
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### Can I build an electrostatic simulation of conductive objects using just the method of images?

I wish to build a simulation of self-assembling wires. Think lots of ball bearings in a 20KV electric field and they form emergent structures. If I use the method of images to figure out what the ...
238 views

### Is a 2021 MacBook Air sufficient for modeling and simulations research in fluid dynamics?

I code mostly in Matlab, simulating various simple fluid dynamics models. One particular simulation has the potential to become sort of complex, though I believe the set of coupled equations will ...
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### Solving Kepler's Equation with Newton-Raphson Method

Note (2022/03/07): This question is solved. Unfortunately, I'm not able to accept the correct answer by Lutz Lehmann, because I screwed up my registration and the account which posted this question is ...
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### What's the relationship of machine learning and mechanical simulation?

What's the relationship of machine learning and mechanical simulation? Particularly, machine learning is about learning from a large sample and predicting based on filters tuned on that. Mechanical ...
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### Feasibility of synthetic, simulated predictions w/o matching against empirical physical measurement?

Feasibility of synthetic, simulated predictions w/o matching against empirical physical measurement? This has puzzled me lately. So, while it's sometimes common to approach modelling and model ...
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### Any literature that extensively discusses the ability to strongly inter-/extrapolate computationally on little empirical data?

Any literature that extensively discusses the ability to strongly inter-/extrapolate computationally on little empirical data? This topic has fascinated me, but I find that it seems a bit novel. ...
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