The in-line forces acting on an elastically mounted cylinder oscillating in still water

The drag and the inertia coefficients of the in-line force were determined experimentally based on the Morison equation. The interrelationship of the in-line force coefficients with the frequency ratio, the amplitude ratio, and the y-direction response were carefully examined. The experimental results show that the frequency ratio is more important in determining the drag coefficient than either the Reynolds number or the reduced velocity, and that the drag coefficient is highly coupled to the y-direction response. Paper was presented at 1985 SEM Spring Conference on Experimental Mechanics held in Las Vegas on June 9–14, 1985.     

Pattern search ranking and selection algorithms for mixed variable simulation-based optimization

The class of generalized pattern search (GPS) algorithms for mixed variable optimization is extended to problems with stochastic objective functions. Because random noise in the objective function makes it more difficult to compare trial points and ascertain which points are truly better than others, replications are needed to generate sufficient statistical power to draw conclusions. Rather than comparing pairs of points, the approach taken here augments pattern search with a ranking and selection (R&S) procedure, which allows for comparing many function values simultaneously. Asymptotic convergence for the algorithm is established, numerical issues are discussed, and performance of the algorithm is studied on a set of test problems.