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\centerline{\bf What will be feasible: 1 PetaFlops Sustained Machine (20 years ?)}
\bigskip
\line{Assume a 3D problem which: \hfill}
\smallskip
\item{$\bullet$} is computed for 50 turnover times,
\item{$\bullet$} uses 5 points to resolve the dissipation scales,
\item{$\bullet$} has 5 ($\rho,Vx,Vy,Vz,P$) + 2 (chemicals) = 7 variables,
\item{$\bullet$} uses 7 (physical) + 4 (scratch) = 11 arrays,
\item{$\bullet$} dumps 1000 snapshots,
\item{$\bullet$} performs 4,000 FP/grid point.
\medskip
\noindent
Use the estimate that the number of degrees of freedom required
to represent fully developed turbulence scales as $(L/l)^3 \sim Re^{9/4}$.

$$
\table
\tablespec{\c\c\c\c\c\c\c}
\body
{
\hline
| | | | | | | |\end
| N | Re | FP/Run | Nsteps | Core Mem. | Storage | Exec. Time |\end
| | | | |  (11 arrays) | (7 vars/1000 dumps)| |\end
\hline
| | | | | | |  |\end
| $2048.^3$ | 3,042 | $6.8\ 10^{18}$ | 200,000 | 755 GB | 481 TB | 2 hrs |\end
| | | $3.4\ 10^{13}$FP/step | | | | 0.04s/step | \end
\hline
| | | | | | | |\end
|$16,384^3$ | 48,670 | $2.8\ 10^{22}$ | 1,600,000 | 387 TB | 387 PB | 7,818 hrs |\end
| | | $1.7\ 10^{16}$FP/step | | | | 18s/step  | \end
\hline
}
\endtable
$$
\bye
