Recent content by Bucky

I'm trying to work through an explanation of how a ray-sphere intersection can be solved algebraically from here: http://wiki.cgsociety.org/index.php/Ray_Sphere_Intersection My problem is at this step: I don't understand how they've expanded the formula. I thought you just multiplied...

sorry I guess my post was rather vague. Let's try again The Navier Stokes equations for incompressible fluid flow are the following: \frac{\partial u} {\partial t} = -(u. \nabla )u - \frac {1} {\rho} \nabla p + v \nabla ^2 u + f \nabla .u = 0 The second equation (the...

Hi, I've been doing some work with the NS equations. I've read a few papers by fellow undergrads that imply a relationship between the helmholtz-hodge decomposition and the pressure equation. As far as I can see, they're both separate ways of resolving the problem of keeping the flow...

Homework Statement Hi, I'm trying to follow the proof for the statement \nabla . u = 0 I'm basing it off this paper: http://delivery.acm.org/10.1145/1190000/1185730/p1-bridson.pdf?key1=1185730&key2=4151929021&coll=GUIDE&dl=GUIDE&CFID=25582973&CFTOKEN=82107744 (page 7, 8) In...

ok, is method right? Regardless of the size of the field, are you still doing "that" to each element?

I've been reading up on these three recently, and wondered if anyone could confirm what I think they do. I'm not 100% I understand these. del (\bigtriangleup), when applied to a scalar, creates a vector with that scalar as each of the XYZ values. eg \bigtriangleup . x = (x,x,x)...

ok I spoke to my tutor about it and he explained how to do these, which made things a lot clearer. I've moved onto doing the next question, and I get one root but i can't get the other two.. A = \left(\begin{array}{ccc}-1&1&-1\\1&-1&-1\\-1&-1&-1\end{ar ray}\right) D(\lambda) =...

sorry yeah that 2 should be a 1 (changed it in origonal post). either way, how do i take this expression and get three roots from it? book gives 2, 3, 6 as the results.

Homework Statement Find the eigenvalues and eigenvectors of A = \left(\begin{array}{ccc}5&1&1\\1&3&1\\1&1&3\end{array}\right) The Attempt at a Solution The problem I'm having is finding the eigenvalues for the matrix. In 2d matricies it's not too bad, but in 3d the...

ok i looked at that wiki article, and del is used to mean a lot of things. what's it supposed to be representing here? I noticed it has some relation to fields too :/ if i was planning to use this in an application, say to find the acceleration each frame. could i just rearrange the...

Hi, hope this is the right area. Also please excuse me completley ignoring the template, I don't think it's applicable for the problem. I'm an honours year student in a comp sci course and I've decided to do an implimentation of Smooth Particle Hydrodynamics in a 3d application as my topic...

Homework Statement Use the integrating factor to solve the first order differential equation dy/dx + (2/x)y = 1 - 2/x subject to the initial condition y(1) = 2The Attempt at a Solution I have the full answer (it's an example), but my lecturer is notorious for omitting steps, to my constant...

At this stage I'm really interested in just understanding the ground work. What equations do I use? How do you represent a volume of water? How do you calculate changes in the body of water? Like i said, everything I've looked at starts with a general overview of what CFD is and why it's...

well the problem is that most of the information is from university courses with modules on on how to use "piece of software X" to find what they want, not an explanation of how to build some form of software. i tried looking for that Verstaag chap, but came up blank. :/

Hi, hope this is the right area for this. I'm currently doing preliminary research for my computer science dissertation. I'm thinking of doing something in CFD...either representing the effects of wind on fur, or simulating a river flowing. Most CFD 'googles' have resulted in me finding...