Tech Briefs

Manifold: Solution with fine mesh, Re = 7000

Turnaround duct: Solution with fine mesh, Re = 500

                 Manifold, coarse mesh                             Turnaround duct, coarse mesh

The Solution of Large Fluid Flow Models in ADINA

Much improved solution times have been achieved in our new
algebraic multi-grid solver. Please see the July 15, 2006 News.

We have accomplished major new exciting developments in fluid flow and fluid-structure interaction (FSI) analysis capabilities. These developments include more effective FCBI fluid flow elements and a more efficient algebraic multi-grid (AMG) solver. These together significantly decrease the solution times and use of memory. We will show many examples demonstrating these major improvements in the forthcoming ADINA News.

In the present News we show two examples of 3-D fluid-flow problems that were solved with increasingly finer mesh densities using the new AMG solver and the new FCBI elements. The manifold problem was analyzed with a fully unstructured mesh of tetrahedral elements, while the turnaround duct problem was analyzed using brick elements. For both problems a SINGLE processor (900 MHz) with double precision was used.

For the manifold problem we solved about 12 million degrees of freedom in 21 hours, using 2.9 GB of memory.

For the turnaround duct we solved about 9.3 million degrees of freedom in 20 hours, using 3.2 GB of memory, see below. Note that the solution times and memory use increase about linearly with the number of equations considered --- which is an important result!

Of course, these solution times will be reduced on multi-processor machines, and will depend on the number of processors used. We are now finalizing the parallel-processing of the algorithms and will show results in forthcoming News. Also, we are exploring the use of single precision to decrease the amount of memory used.

An important point is that the new fluid flow capabilities can be used in FSI analyses and enable the solution of much more complex problems than could so far be considered.

Please see the July 15, 2006 News for much improved solution times.