Hi all,
I have learned that the hydrodynamic entrance length of a channel (to form fully developed laminar flow) is correlated to the Reynolds number, because the shear effects have to propagate inwards from the walls of the channel. However recently I found out that there is a 'minimum' to the...
Hi Colen
Could you give a little more detail of what you're trying to do exactly. What do you mean by 'the output of the plug flow model is the CSTR model', do you mean that this is physically the case, i.e. you have a PFR connected to a CSTR, or do you only use the PFR to 'model' a time delay...
Hi,
Is there a command available that makes the compiler ignore all write(*,*) statements?!
The thing is, I'm working on a code which will eventually run for several hours (perhaps days) to complete a single run. At the moment I'm testing so I write a lot of data to the screen in order to...
Stokes' paradox was first found for a cylinder perpendicular to the flow, but the same effect (and for the same reason) is present for flow parallel to the cylinder. The basic problem is not the direction of flow but rather the fact the effect of inertial as compared to viscous forces are no...
The example you gave in the first post is such a function: |x|.
That function is perfectly differentiable (it will be 1 or -1) throughout the domain, but it changes sign with 'infinite' slope at x=0.
I've found useful equations from Batchelor (1970) and Keller (1976) who use 'slender-body theory' in which the rod is approximated as a line of stokeslets (singular force terms)
mmm, seems like I found the famous Stokes' paradox. For other people reading this and wondering how to solve it: take a look at Oseen's approximation method
Hi,
I'm looking for a correlation of the drag force on a cylinder in parallel creeping (stokes') flow (i.e. the flow is alongside the axis of the cylinder). My length-to-width ratio is such that assuming an infinitely long cylinder is perfectly okay.
Does anyone know where I can find such a...
Homework Statement
I have a cylinder of radius R translating (in radial direction) with velocity U in a viscous fluid at Re<<1. Find the force exerted on the cylinder per unit lengthHomework Equations
Re<<1 so the Navier-Stokes equation simplifies to the Stokes equation:
\nabla P=\mu \nabla^2 v...
Homework Statement
A flow field is considered to be steady two-dimensional and can be described by the following
velocity components in the xy- or r\theta-plane at the front half of the cylinder:
u_r=V\cos\theta\left(1-\frac{a^2}{r^2}\right)...
Oops, little to quick in my steps. So instead of 4 i take 2 in those equations.
I think I got it now:
d\textbf{s}=dx\textbf{i}+dy\textbf{j}=\left(\frac{ dx}{d\theta}\right)d\theta\textbf{i}+\left(\frac{d y}{d\theta}\right)d\theta\textbf{j}=-2\sin \theta...
Homework Statement
A flow field on the xy-plane has the velocity components
u=3x+y
v=2x-3y
Show that the circulation around the circle (x-1)^2+(y-6)^2=4 equals 4\pi
Homework Equations
The circulation \Gamma around a closed contour is:
\Gamma=\int_C\vec{u}\cdot d\vec{s}The Attempt at a...
How do you define 'performance'. If you mean the computational time, then yes BCRS is worse then CRS because it is 'harder' to find a specific matrix element.
Remember: sparse matrix storage modes are SPACE-savers, not TIME-savers
Have you tried http://www.nr.com/oldverswitcher.html" ...