IPET Report 3 Vol VIII

The spatial pattern of surge and waves depends primarily on R max, X and θ. Since the effect
of these parameters at a given geographic location is generally non-monotonic, interpolation
involving these parameters would not produce accurate results. In addition, these parameters
interact among themselves. Hence, all combinations of R max, X and θ in Table 6 must be run
using the MR model. The use of only 3 levels of R max in Table 6 reduces the computational
effort in the MR runs.
The LR runs have shown that, for given R max, X and θ, the water level at each geographical
location depends smoothly on ΔP , V, and B. Therefore a smaller number of levels of these
parameters were considered and water levels calculated for the other levels through
interpolation. This has led to the MR run plan in Table 7.
One may reduce the number of MR runs even further. From the LR runs, it was determined
that the multiplicative effect of Holland’s B on the surge depends mildly onΔP and V. Therefore
there is no need to run different values of B with each combination of ΔP and V. This produces
the MR plan in Table 8, which comprises two sub-factorials of the levels in Table 7, with a total
of only 1155 runs.
Table 7
Parameter Levels for Mid-Resolution Runs
Parameter Levels for mid-resolution analysis
ΔP (mb)
V (km/h)
Xcos(θ) (km)
θ ��
R max
B
---------------
ΔP R (t)
V R(t)
R max (t)
B(t)
α
No. of cases 2835
41, 80, 115
8, 21, 36
-130, -90, -50, -10, 30, 70, 110
-60, -30, 0, 30, 60
10%, 50%, 90% quantiles from Eq. 8-2
5%, 50%, 95% quantiles from Eq. 8-3
------------------------------------------------------------
smooth ΔP R,0.5(t) curve in Figure 8-5
smooth V R,0.5(t) curves in Figure 8-6 depending on V
from R max, ΔP(t) and Lat(t); see Eq. 8-5
from B, R max and Lat(t); see Eq. 8-6
0.035 + 0.0005ΔP
VIII-34 Volume VIII Engineering and Operational Risk and Reliability Analysis
This is a preliminary report subject to revision; it does not contain final conclusions of the United States Army Corps of Engineers.