A Foul-Weather Fountain 251 a Foul-Weather fountain lyan K Card R Ernie e esser Jeffrey H Giansiracusa University of Washin Seattle Wa Advisor: James Allen Morrow Introduction We devise a fountain control algorithm to monitor wind conditions and ensure that a fountain at the center of a plaza fires water high enough to be dazzling while not drenching the pedestrian areas surrounding the fountain We construct a model of a fountain based on the physics of falling water under various wind conditions through computer simulation. Using complex analytic techniques, we model the wind flow through the plaza and estimate how anemometer readings from a nearby rooftop relate to plaza conditions We construct four algorithms-two intelligent algorithms, a conservatiy approach, and an enthusiastic system-to control the fountain We devise a measure of unacceptable spray levels outside the fountain and use this criterion to compare performance. First, we examine the behavior of these algorithms under general abstract wind conditions. Then we construct a wind signal generator that simulates the conditions of several major cities from meteorological database data, and we compare the performance of our control systems in each city Simulations show that the Conservative and enthusiastic algorithms both perform unacceptably in realistic conditions. The Weighted Average Algorithm works best in gusty cities such as Chicago, but the Averaging Algorithm is superior in calmer cities such as Los Angeles and Seattle The control algorithm cannot possibly respond to changes in conditions at anything below the 10 s scale, since wind is highly variable and the response of the anemometer is somewhat slow [Industrial Weather Products 2002]. The goal is therefore to design the algorithm to operate on a time scale of 10 s up to a couple of hours and adapt the height of the fountain to a maximum safe level The UMAP Journal 23(3)(2002)251-266. Copyright 2002 by COMAP, Inc. Allrights reserved Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial dvantage and that copies bear this notice. Abstracting with credit is permitted, but copyrights for components of this work owned by others than COMAP must be honored. To copy otherwise, to republish, to post on servers, or to redistribute to lists requires prior permission from COMAPA Foul-Weather Fountain 251 A Foul-Weather Fountain Ryan K. Card Ernie E. Esser Jeffrey H. Giansiracusa University of Washington Seattle, WA Advisor: James Allen Morrow Introduction We devise a fountain control algorithm to monitor wind conditions and ensure that a fountain at the center of a plaza fires water high enough to be dazzling while not drenching the pedestrian areas surrounding the fountain. We construct a model of a fountain based on the physics of falling water droplets considered as a particle system. We examine the behavior of a fountain under various wind conditions through computer simulation. Using complex analytic techniques, we model the wind flow through the plaza and estimate how anemometer readings from a nearby rooftop relate to plaza conditions. We construct four algorithms—two intelligent algorithms, a conservative approach, and an enthusiastic system—to control the fountain. We devise a measure of unacceptable spray levels outside the fountain and use this criterion to compare performance. First, we examine the behavior of these algorithms under general abstract wind conditions. Then we construct a wind signal generator that simulates the conditions of several major cities from meteorological database data, and we compare the performance of our control systems in each city. Simulations show that the Conservative and Enthusiastic algorithms both perform unacceptably in realistic conditions. The Weighted Average Algorithm works best in gusty cities such as Chicago, but the Averaging Algorithm is superior in calmer cities such as Los Angeles and Seattle. The control algorithm cannot possibly respond to changes in conditions at anything below the 10 s scale, since wind is highly variable and the response of the anemometer is somewhat slow [Industrial Weather Products 2002]. The goal is therefore to design the algorithm to operate on a time scale of 10 s up to a couple of hours and adapt the height of the fountain to a maximum safe level. The UMAP Journal 23 (3) (2002) 251–266.
c Copyright 2002 by COMAP, Inc. All rights reserved. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice. Abstracting with credit is permitted, but copyrights for components of this work owned by others than COMAP must be honored. To copy otherwise, to republish, to post on servers, or to redistribute to lists requires prior permission from COMAP