Browsing by Author "Song, Charles C. S."
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Item Application of Burean of Reclamation Gstars to Willow Creek Unprotected Spillway(St. Anthony Falls Hydraulic Laboratory, 1987-04) Song, Charles C. S.; Zen, YifanWhen there is a significant change in discharge or sediment load, due to flood or construction of a reservoir for example, erosion and deposition cause the geometry of an alluvial channel to change rapidly. in order to achieve a new equi1ibrium condition. Because the process is a highly complex mu1ti-component, multi-dimensional, and time dependent process its complete mathematical modeling is not feasible at the present time.Item Application of Bureau of Reclamation's GSTARS To Lake Mescalero Dam Spillway(St. Anthony Falls Laboratory, 1989-01) Song, Charles C. S.; Zheng, YifanWhen there is a significant change in discharge or sediment load, due to flood, for example, erosion and deposition cause the geometry of an ,alluvial channel to change rapidly in order to achieve a new equilibrium condition. Because the process is a highly complex multi-component, multi-dimensional, and time-dependent process, its complete mathematical modeling is not feasible at the present time. In order to predict the variations of channel width, as well as the river bed elevation, it is necessary to distinguish the sedimentation at the bank from that of the bed. The Bureau of Reclamation GST ARS model adopts a new concept which combines the conventional one-dimensional flow model with the theory of minimum energy dissipation rate such that the variation in channel shape can be calculated efficiently. A detailed description of the original GSTARS model is given in the User's Manual of the Bureau of Reclamation [1]. Because the GSTARS model is relatively new, the Bureau of Reclamation decided to carry out some case studies in order to verify and improve the model. The first case study, the erosion of the unprotected spillway of Willow Creek Dam in Montana due to hypothetical floods, was completed in April, 1987 [2]. Because there were no erosion data due to the hypothetical floods, the accuracy of the results could only be judged qualitatively and by comparing with other estimates. The results appeared quite reasonable and encouraging. The actual channel erosion of Mescalero Dam emergency spillway in New Mexico due to the 1984 flood has been selected as the subject of the second case study. The topographic data taken on June 12, 1979 was used as the initial condition. The water level data taken during the 1984 flood was used to calculate the flood hydrograph. In addition, sediment samples were taken and analyzed and used as input data. Four channel cross sections measured immediately after the 1984 floods were used to determine. the accuracy of the model output. During the course of the second case study; it was necessary to add three new features to the GSTARS model. The three new features are, in order of importance, (1) the bank slope stability constraint, (2) the erosion due to water fall at the upstream end, and (3) the lateral sediment transport due to secondary current in a bend. With these additional features, the modeled results agreed very well with field data, except at a station where a branch channel meets the main channel. The present GST ARS model is not capable of modeling channel junctions.Item Data Analysis and Numerical Modeling of Flow in the 1:14 Scale LCC Model(St. Anthony Falls Hydraulic Laboratory, 1989-06) Song, Charles C. S.; Yuan, Mingshun; Wang, Qun; He, JianmingA 1:14 scale model of the Large Oavitation Ohannel (LOO) was built and tested by Voith Hydro, Inc. [l]. The velocity profiles on the central plane of symmetry was surveyed using Pitot tubes at stations P1 to P7 as shown in Fig. 1. Later, additional measurements were made with LVD at stations Ll to L4 [2]. These measurements indicated the existence of unusually thick boundary layers on the top wall at the test section and poor flow quality in the diffuser when the honeycomb for turbulence management was present. Some improvements on mean velocity profiles were found possible by either completely or partially removing the honeycomb.Item The Dynamic Mixed-Flow Model for Metropolitan St. Louis Sewer District(St. Anthony Falls Laboratory, 1979-09) Song, Charles C. S.; Leung, Kim Sau; Cardle, James A.The existing facilities associated with wastewater ove~flows from the Bissell watershed include wastewater collection system elements in 23 subwatersheds and flood protection facilities in 24 subsystems. Some collection system trunk sewers are over 125 years old. Portions of the existing trunk sewe~s have recently been rehabilitated as parts of pollution abatement and flood p~otection projects. Majo~ flood protection works and pollution abatement facilities were completed in the last 10 years.Item An Experimental Study of The Hydroelastic Instability of Supercavitating Hydrofoils(St. Anthony Falls Hydraulic Laboratory, 1967-02) Song, Charles C. S.; Almo, JohnSome experimental findings concerning the flutter characteristics of two-dimensional supercavitating flat plate hydrofoils are reported herein. The experiment was carried out in a freejet water tunnel using wedge-shaped hydrofoils (practically rigid) elastically supported to permit two-degree of freedom motions in translational and rotational modes. Critical flutter speed, flutter frequency, flutter amplitude ratio, and damping factor were measured for various elastic and flow conditions. The measured stability boundary curves agree, qualitatively,with an existing linear theory.Item Extended Phase A-2, Large Cavitation Channel, Davld Taylor Naval Ship Research and Development Center(St. Anthony Falls Laboratory, 1984-08) Arndt, Roger E. A.; Song, Charles C. S.; Silberman, Edward; Killen, John M.; Wetzel, Joseph M.; Yuan, MingshunIt was suggested that a mild contraction located immediately upstream of the pump may improve the quality of flow which is expected to be quite nonuniform coming from the diffuser and the first and second elbow. To investigate the effect of the contraction ratio, the AROl computer model previously used in the Phase A-2 studies for the Large Cavitation Channel (LCC) main contraction design was applied to the pump contraction. As shown in Fig. 1, the contraction is assumed to be 5.563 m long and of circular cross section. Area contraction ratios of 0, 10, 20 and 30 percent were used. There is a fixed shaft of constant diameter along the centerline of the contraction. Two different shaft diameters, 0.508 m and · 1.016 m, were used based on information available at the time the study was conducted~ Initially, a fifth order polynomial was used for the contraction profile. The profile was later changed to a straight line because the contraction is so mild that the flow is not significantly affected by the boundary shape. Due to symmetry about the vertical plane, only half of the flow region was modeled. Different types of nonuniform inflow velocity profiles were studied. A total of 46 modeling runs covering various geometrical and flow conditions as well as different modeling parameters were made.Item Hydraulic Analysis Of The Proposed Additional Treatment Facilities(St. Anthony Falls Laboratory, 1982-12) Song, Charles C. S.; Gavali, SharadchandraThe existing Van Lare Treatment Plant has a design capacity of 150 MGD. As a part of the combined sewer overflow abatement program an additional primary treatment facility is being designed. The new primary treatment facility will be located next to the existing facility and will have the design treatment capacity of 270 MGD and the hydraulic capacity of 400 MGD.Item Hydraulic Transient Analysis of Tarp Phase II System(St. Anthony Falls Hydraulic Laboratory, 1988-09) Guo, Qizhong; Song, Charles C. S.The O'Hare System of the Tunnel and Reservoir Plan (TARP), which services 11.2 square miles of combined sewers, as shown in Fig. 1, is the smallest of the four systems comprising the 352-square mile combined sewer service area operated by the Metropolitan Sanitary District of Greater Chicago (MSDGC). After completion of this system in 1980, the O'Hare System area has still experienced problems, including basement flooding from sewer back-up and foundation seepage, overbank flooding, transportation delays caused by flooded streets, water quality degradation of area watercourses from combined sewer overflow, and public health hazards resulting from sewer back-ups. The average annual damage due to flooding in the O'Hare System are estimated to be in excess of $2.5 millionItem Hydraulic Transient Modeling of Tarp Systems(St. Anthony Falls Hydraulic Laboratory, 1988-03) Song, Charles C. S.; Guo, Qizhong; Zheng, YifanUnder the agreement of November 1, 1986, between the Metropolitan Sanitary District of Greater Chicago and the University of Minnesota, the St. Anthony Falls Hydraulic Laboratory of the University conducted mathematical modeling of the recently completed portions of the Tunnel and Reservoir Plan (TARP), both the Mainstream System and the Calumet System of Greater Chicago, for the purpose of establishing optimum operating procedures and additional structures to control hydraulic transient problems. The scope of the work was later extended to include the Des Plaines System and the 13A tunnel when operated independently of the Mainstream System.Item Hydraulic Transient Modeling of TARP Systems(St. Anthony Falls Laboratory, 1992-08) Song, Charles C. S.; Lin, Wenchin; Gong, CuilingThe Mainstream System excluding North Branch and the Calumet System excluding Indiana A venue tunnel of Greater Chicago were studied in 1988. The solutions based on these systems were suggested in a project report [1)1 in 1988. Since then a new North Branch tunnel is being planned to join the original Mainstream System, and the Indiana A venue tunnel to be added to the Calumet System, it therefore becomes necessary to reevaluate the previously suggested operational plans. A new computer simulation and solution alternatives for these expanded systems are described in this report. The 'North Branch System has also been studied separately and reported herein.Item Hydraulic Transient Study of Mainstream & Des Plaines TARP Phase II Systems(St. Anthony Falls Hydraulic Laboratory, 1994-07) Song, Charles C. S.; He, Jianming; Liu, Ying; Gong, CuilingNumerical studies of hydraulic transients for the TARP Phase I system were conducted in 1988. and 1992. These studies revealed that due to storage and/or conveyance limitation of the TARP Phase I Mainstream system, inflow must be substantially reduced to avoid geysering problems induced by hydraulic transients. Different inflow control solutions to different cases of the TARP Phase I were suggested in the previous project reports. TARP Phase II is designed to add additional water storage and increase the conveyance ability. This study is to investigate the extent and nature of hydraulic transients in Mainstream/Des Plaines TARP Phase II and to evaluate its design performance using computer modeling. The fully dynamic transient mixed flow mathematical model (MXTRANS) developed at the University of Minnesota was used for this study. To evaluate the hydraulic performance of the TARP Phase II System, including the Phase I Mainstream tunnel, Phase II Relief tunnel, and Phase I Des Plaines tunnel with or without four planned reservoir stages, four groups of modeling configurations for the systems as listed below are being considered Group A: Stage I Mainstream (Mainstream alone) Tunnel System Group B: Stage II Mainstream (Mainstream. With Relief Tunnel) System Group C: Des Plaines With or Without Mainstream System Group D: Interconnected Des Plaines and Mainstream Systems (Mainstream with Relief Tunnel and Des Plaines Tunnel)Item Hydraulic Transient Study of Mainstream Tunnel System and Control System(St. Anthony Falls Hydraulic Laboratory, 1994-10) He, Jianming; Song, Charles C. S.; Liu, Ying; Cuiling, GongNumerical studies of hydraulic transients for the TARP Phase I system were conducted in 1988 and 1992. These studies revealed that due to storage and/or conveyance limitations of the TARP Phase I Mainstream system using the Keifer/Song maximum hydrograph, inflow must be substantially reduced to avoid geysering problems induced by hydraulic transients. In order to improve the hydraulic transient condition, TARP Phase II has been proposed to add additional water storage and increase the conveyance ability. A hydraulic transient study for the TARP Phase II system was also conducted recently. However, before the TARP Phase II is completed, a reasonable tunnel operation method for the current TARP Phase I system must be sought to minimize the potential of the hydraulic transient problems. This study is to investigate the extent and nature of hydraulic transients in the current TARP Phase I Mainstream tunnel under the existing flow control structures for different hydrographs.Item Hydraulic Transient Study of Narragansett Bay Commission CSO Storage Tunnel(St. Anthony Falls Laboratory, 1999-11) He, Jianming; Song, Charles C. S.One concern of the tunnel system is the potential for hydraulic transients during the tunnel filling process. Under some conditions, strong storm inflow to a tunnel may generate severe hydraulic surge in the tunnel, and consequently water may shoot up from the dropshaft like a geyser, which may result in structural damage to surface facilities and other environmental problems. For example, in Minneapolis, USA, a severe storm in 1997 caused a geyser 17 m above the ground from the storm water tunnel. The purpose of this study is to examine the possibility of any geysering and other hydraulic transient problems during the tunnel filling process based on the proposed tunnel configuration design and inflow under different tunnel operating conditions using our wellestablished hydraulic transient computer simulation model (MXTRANS).Item Hydraulic Transient Study of Narragansett Bay Commission Tunnel System(St. Anthony Falls Laboratory, 1995-08) He, Jianming; Song, Charles C. S.; Liu, YingThe purpose of this study is to evaluate the hydraulic transient status in the proposed Narragansett Bay Commission (NBC) Tunnel System in north central Rhode Island. The tunnel system is designed as an off-line storage facility. As shown in Fig. 1, the tunnel system consists of Main Spine Tunnel and Seekonk Tunnel, as well as 18 dropshafts. For a larger storm, the inflow must be controlled to prevent overfilling. At a circumstance of inflow control gate failure at some dropshafts, the flows exceeding the storage capacity of the tunnel may overflow into the Mosshasuck River through an "extreme event overflow". This structure is proposed to be located in the vicinity of OF 009/010.Item Hydraulic Transient Study of Passaic River Flood Protection Tunnel(St. Anthony Falls Hydraulic Laboratory, 1994-09) He, Jianming; Song, Charles C. S.; Liu, YingThe purpose of this study is to evaluate the hydraulic transient status in the proposed Passaic River Flood Protection Tunnel. The tunnel system is designed to convey flood waters from the upstream areas of Passaic River directly into Newark Bay. The tunnel consists of two upstream inlets, the Pompton Inlet and the Spur Inlet, and a 42 ft diameter main tunnel. The main tunnel length is about 20.1 miles (from the Pompton inlet to the downstream end). The distance between the Spur inlet and the main tunnel is about 1.2 miles. The tunnel system will be excavated from 150 to more than 400 ft under ground. From the hydraulic transient point of view, there are the following possible safety concerns in this tunnel system, which need to be evaluated using hydraulic transient computer. simulation program. (1) Surge phenomena induced during the initial filling stage. (2) Water hammer phenomena due to a sudden pressure change. (3) The effects of the surge and water hammer on the inlets, workshafts, and downstream outlet.Item Hydrodynamic Analysis of the Hykat(St. Anthony Falls Hydraulic Laboratory, 1987-06) Song, Charles C. S.; Wetzel, Joseph M.; Yuan, M.; Arndt, Roger E. A.; Killen, John M.The St. Anthony Falls Hydraulic Laboratory has carried out a hydrodynamic analysis of several critical components of a preliminary design configuration of the HYKAT. A sketch of this configuration is shown in Fig. 1. The components subjected to detailed analysis were those of the upper leg, including the contraction, turning vanes of the first elbow, and the turbulent management system. Head loss computations were made for the entire flow circuit. Mathematical modeling was used extensively for analysis of the contraction and the turning vanes. Based on the results of this study, recommendations have been made for some modification to the preliminary design. Some of the results presented here have been previously included in progress reports, and results of additional studies are summarized.Item Hydrodynamic Analysis of the SSL Flow Facility(St. Anthony Falls Hydraulic Laboratory, 1987-03) Song, Charles C. S.; Yuan, Mingshun; Wetzel, Joseph M.A preliminary concept for a gravity flow test facility was evaluated using mathematical modeling techniques. Complete specifications for the hydrodynamic performance were not available. In the absence of these values, parametric studies were carried out to determine the sensitivity of flow quality indicators to dimensional changes. The target flow conditions in a circular test section with a 4 sq ft area were a 90 second test run at a constant velocity of 60 fps.Item Mainstream and Des Plains TARP Tunnel System A Hydraulic Model Study(St. Anthony Falls Laboratory, 2002-01) He, Jianming; Song, Charles C. S.Numerical studies of hydraulic transients for the Phase I Mainstream system of the Tunnel and Reservoir Plan (TARP) were conducted in 1988 [1] and 1992 [2]. These studies revealed that due to storage and/or conveyance limitation of the TARP Phase I Mainstream system, flow must be substantially reduced to avoid geysering problems induced b'y hydraulic transients. Later in 1994 [3], hydraulic transient studies of the preliminary design of Mainstream & Des Plaines TARP Phase II systems were also conducted under various tunnel operation conditions. It was found that a reservoir at the downstream end does little help to reduce the transient problem in the Mainstream system due to the conveyance limitation during the simulated storm event. The main objective of this study is to investigate the hydraulic event which occurred in the TRAP system on June 1, 1999, resulting in flooding of the Dewatering Valve Chambers at the Mainstream Pumping Station, and damage to. the. mechanical and electrical equipment therein. The study uses District operation data, reports and findings, photographs of the damage, rain data, as-built facility plans, and all other available, applicable information to characterize the event. In addition to identifying the underlying causes of the event, the study is also to investigate the methods of operation of the Mainstream and Des Plaines T ARP tunnel systems, separately and in combination, to optimize CSO pollution capture while avoiding adverse hydraulic transient phenomena such as tunnel geysering, severe pressure surges, etc. in T ARP facilities. The study is also to identify possible additional and/or revised control features of the TARP system necessary to achieve the aforementioned optimum operation.Item Mathematical Modeling For Cross-Irondequoit Tunnel And Associated Facility(St. Anthony Falls Laboratory, 1980-07) Song, Charles C. S.; Leung, Kim SauThe Cross-Irondequoit tunnel was originally desic;Jned as a tl:"unk sewer whose main fUnct;i.on was to convey the combineel flow to a pumping station. This system (Fig. 1-1) is located in a developing section of Rochester, New York. It is currently underutili~ed, and it is not expectep to reach cap.acity for another 50 yea:t::'s. ~he system studied consists of a 7 £t elia ... meter, 3 mile long, pO:t::'tion of the Itondequoit Creek interceptor, which ends at the Browncroft junction chamber, followed by a short 12 ft diametet section joining the junction chamber to the transition chamber and a 16 ft diameter, 6 mile long, tunnel connecting the transition chamber and the pumping station. From there the flow is pumped through pressurized conduits to a waste water treatment plant. Eventually,another tunnel will also drain into the wet well.Item Mathematical Modeling of STS Series 60 Turbine(St. Anthony Falls Hydraulic Laboratory, 1992-07) Song, Charles C. S.; Chen, X. Y.Some existing hydro-turbines, especially small turbines, have not been extensively evaluated for their performance and possible upgrading. This may be at least partially due to the fact that the traditional means of evaluation, turbine testing, is quite expensive. The c.osts of design and evaluation can now be substantially reduced by taking advantage of the recent development of computational technology. STS Hydropower Ltd. has contracted with the St. Anthony Falls Hydraulic Laboratory of the University of Minnesota to conduct a preliminary evaluation of the STS Series 60 Francis turbine using the recently developed mathematical modeling program. After completing the simulation based on the geometrical data initially furnished by STS Hydropower, new geometrical data were received and recalculations requested. The new geometry differs from the old one in that the trailing end has been lengthened and the edge sharpened and also a more streamlined leading edge given. Also, calculations of two flow conditions was requested: maximum efficiency condition and maximum output condition. The work has now been completed and the results are described in this report. Some recommendations for future work to improve the efficiency of the turbine are also given.