Cfd Definition and 133 Threads

Hi, I'm have been trying to model an airsoft replica, as an electrical engineer fluid dynamics, thermodynamics is a complete new flied for me and with with help of Ai i have been learning a lot about this subject. So far I have come a long way in making something my first model sort of worked...

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.

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...

For my 12th grade school project, I'm planning to research on the effect of vent ratio on the drag coefficient of round parachutes. My idea was to make small model parachutes and drop them from a height, and derive the drag coefficient after certain assumptions. But I also thought it'd be...

Dear all, I'm currently working on a basic coating application and I'm struggling to get the flow rate stable. I'm trying to figure out how to calculate the theoretical flow rate in the application. The coating is stored in a pressure tank, which we put on an overpressure of 15psi. From the...

Previous post linked here, where a model for the two phase flow of air through a packed bed was developed: https://www.physicsforums.com/threads/modelling-of-two-phase-flow-in-packed-bed-using-conservation-equations.1008754/ The first few comments on this new thread will be copies of the...

I am trying to understand the following code (it starts from line 59) and there are pieces I do not understand. argList::addNote ( "Solver for two incompressible, isothermal immiscible fluids with" " phase-change.\n" "Uses VOF (volume of fluid) phase-fraction based...

Previously, I have seen the derivation of the energy conservation equations for simulation of single phase flow in a porous media (a packed bed). These are the energy equations for the solid and fluid respectively: I understand the derivation, however, these equations will only work when the...

This is my c program below. Again everything works as expected up until the highlighted lines or the second for loop. When i run my program to output the arrays contents i get bizarre numbers that are not correct. # include <math.h> # include <stdlib.h> # include <stdio.h> # include <time.h>int...

Hello! I am investigating some preliminary aerodynamics on a regional turboprop and for the drag model the surface roughness height of the airplane is required as an input. For this i do not have any data. In which range are the typical values for modern aircraft surfaces? Thanks a lot!

Hi there, attached were the results: https://prnt.sc/v3yg1f Both are negative and need to be added together to get the torque force. Calculations are from a model of specified radius and input air speed, its a turbine. Just need help in understanding what the negative results mean and how they...

Hi PF! I'm running a CFD (computational fluid dynamics) program OpenFOAM. Liquid is sucked from a tank, where the velocity at the tank outlet (suction point) is controlled by a python script. The boundary condition for velocity at the outlet is below, line 4 being the velocity prescribed at...

Hi PF! Hello all I just downloaded gmsh on Linux 64 bit running Ubuntu 18.04. When I attempt to open a .stp file I created in salome, the program crashes, leaving a terminal output "segmentation fault (core dumped)". Any idea what is going on? The step file is...

I'm running computational fluid dynamic simulations and am looking into building a desktop. But there are so many options. At this budget, what would you buy? Is it better to buy used CPUs, etc?

Hi PF! Does anyone know how to pin the fluid-solid contact line in OpenFOAM? There has to be a way to do this, and I've tried the cfd-online community but they're largely inactive and consequently no one has replied to my question. Any help or guidance is greatly appreciated!

Hi PF! I recently installed the computational fluid dynamics software oomph-lib, which is similar to OpenFOAM. After installing, I'm trying to run a tutorial provided with the program, described here. I think all I need to do it run the .cc file here, so I type into the terminal >> gcc...

Summary: Counterfactual Definitiveness and Many World's Interpretation Sorry for all these threads, my noetic fluids and bursting. Wiki states the following: In quantum mechanics, counterfactual definiteness (CFD) is the ability to speak "meaningfully" of the definiteness of the results of...

Hi PF! I'm trying to follow these instructions to install an open-source CFD software on Ubuntu: http://oomph-lib.maths.man.ac.uk/doc/the_distribution/html/index.html#download After downloading the tar file http://oomph-lib.maths.man.ac.uk/tar_file_directory/, I type the command >> tar xvfz...

(New thread following up to a conversation in another thread). I'm using SimFlow 3.1 with OpenFOAM 5 on Linux to try to evaluate the drag coefficient of a water rocket body, constructed from a 2-liter Coke bottle with a conical nose, traveling through air at 77 m/s. This should be a simple...

Tom Crawford (sporting a Navier-Stokes tattoo) talks about the famed equations - subject of a $1m Millennium Prize.

Hi PF! I'm simulating two fluids, air (blue) and water (red), in a 2D rectangular channel. See picture below: I've turned gravity and viscosity off, and have ##\rho_w=1000## kg/m^3 and ##\rho_a = 0.01## since it cannot be zero. I've also enforced a static contact angle of ##\theta = 71^\circ##...

One thing that confuses me is the physical speed and sound speed. The lattice sound speed cs=1/sqrt{3} corresponds to the physical sound speed for isothermal flow (sqt{RT}). Why isn't the physical speed (e.g. inlet speed up of lid cavity) converted and use accoringly? $$c_p=\sqrt{RT}≈330m/s...

Hello, I am using CFD to analyse a Kaplan turbine and am unsure on how to interpret the torque values as they come as x, y and z components. My understanding is that the z component in this case will determine the rotation direction depending on whether it is positive or negative however I am...

Hi everyone, I am researching how numerical simulations have evolved over the years in nuclear reactors for assessing the thermal hydraulics inside the reactor core. I have found vague information in regards to the three different main numerical techniques but want to learn more. So far...

Dear All I am an undergraduate student studying in physics. I would probably get into research that needed fluid dynamics and CFD (computational fluid dynamics) skills. Previously I have not been taking a formal fluid dynamics course since there is none. I would like to pick up those skills by...

Hi, This is my first post on the PhysicsFormus I am trying to design an inlet and outlet for an axial fan and calculate velocity and pressure profiles in the duct. See the sketch attached. The ultimate goal is to carry out a CFD study but I was wondering if there is an analytical solution for...

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...

I am currently an "intern" at a company for a position primarily involving drafting cell site equipment. That is going quite well. But the owner of the company (an old friend of mine) has asked me to look up computational fluid dynamics softwares and begin to tinker with one, because he is...

Hello, Does anyone know if a finite element skeleton source code exists. Finite element can be used for structural memebers, gas dynamics, etc. But the over all stepping software is the same and then just input the core equations. My application is for pseudo one dimensional compressible...

Hi, Can anyone direct me to some literature that describes the numerical solution of full Maxwell's equations and Navier-Stokes equations for two-phase/multi-phase flows in coupled electric and magnetic fields. Thanks!

Hoping to get some help on a stability analysis of this setup...

Is it possible to couple a thermal hydraulics code with a kinetics one ? , main purpose is to study the behaviour of kinetics due to a LOCA or any other changes regarding the coolant/moderator flow " talking about a PWR " .

What is the difference between counterfactual definiteness on one side and realism on the other? And what are their definitions? (references will be welcome if given).

Hi everyone, This is my first post as I am a new member here. I am trying to simulate an opening of a bascule bridge and study the flow over it in Fluent. I simplified the problem by allowing the bridge to be represented by a flat plate and I used Reynold's Number scaling to scale my dimension...

I've previously studied and used the k-epsilon turbulence model within Ansys to model water in a small stirred vessel. I am now interested in CFD models appropriate for modeling flue gas dispersion. I'd like to know: What additional considerations are required for modeling a gas as opposed to...

I have created a savonius turbine model with 2 blades using 3D gambit. I want to simulate the flow of air flowing so as to drive the turbine savonius spin (unsteady, incompressible). Geometry consists of 3 volume boxes (domain tunnel flow), cylinder (domain grid interface), blade savonius...

I am a Phd student working in a technological center. My work is related to CFD simulations by using OpenFoam coupled to discrete element method. I am very interested in mathematical and physical background of continuum mechanics both solid and fluids. I am loking forward to solve my interests...

Hello, After Favre averaging the momentum equation for an inviscid flow, the following can be obtained: $$\frac{\partial}{\partial t} \left(\overline{\rho}\tilde{u}_i \right) + \frac{\partial}{\partial x_j}\left( \overline{\rho}\tilde{u}_i \tilde{u}_j \right) + \frac{\partial...

I'm having fluid dynamics classes right now and I'm enjoying it very much (much more than my solid mechanics classes, by the way). Also, I do like programming and computer science, and CFD looks like a very interesting field. I'm developing a real interest for it. One question for those who are...

I am thinking of the usual "Alice and Bob" type scenario. If I choose to view the measuring instruments of Alice and Bob as "classical objects in spacetime", am I not then forced to say the following as well? 1) The joint-state of the measuring instruments is separable throughout the whole of...

Hey guys and gals, In my 4th year I got interested in cfd while doing a flat plate case. Fast forward to after grad and while I am looking for a job(Still looking :( ) I have been playing with Linux and open foam. I looked into astrophysics and plasma physics and such as they interest me to. So...

Hi everyone! I am a soon-to-be graduate of the Technical University of Munich and work in the field of Computer-Aided Engineering (CAE) – looking to exchange experience and ideas on CFD, FEA,Thermal Analysis and their applications in product design!

I've been thinking about entrepreneurship in the engineering field. Unlike other fields like computer science, where small companies with small investments often end up becoming huge business, engineering is usually a very expensive thing. So consulting is a way for those who don't want to work...

Can Autocad inventor be used as a cfd software such as ansys fluent? Thank you.

I simulated an incompressible turbulent flow across a tube. I managed to solve it using OpenFoam and the results seem to be right. However, I noted some vacuum pressure after the sudden expansion but can't figure out why the pressure decreases and then increases again. According to Bernoulli's...

I did a lot of googling but could not find a satisfying answer to my question, hence a post here. Question: How to solve (or close) the isothermal incompressible Navier-Stokes equations for an isothermal compressible fluid? Situation: We have a compressible fluid, for example a gas. The flow...

Case One : In Bell test violations can outcomes be they (1) contextual outcomes ( not pre - encoded in measured object but arise in interaction with object and measurement apparatus) be distinguished from (2) non realism /non counter factual. And (3) from non local effects in a space like...

Hi, my background is in mathematics, and theoretical physics. I am new to the realm of solving PDEs using Finite element methods, does anyone know of any good introductory level textbooks for course notes? I had a poke around online and couldn't find anything overly useful. Also I am...

Hi, I'm working on a project of coupled simulation involving MCNP and Fluent, and having trouble with how to apply the pseudo-material method in cross section handling. Is there any related material or tutorial? Or, does anyone know the procedure of applying the method and what kind of files the...

I'm looking for an example of CFD analysis on a pressure reducing regulator. I think may be fairly complicated because the main valve position is not fixed but rather controlled by the pressure differential acting across the valve, the main valve spring, and the load spring minus the pressure...