Spoiler for Wave Improvement at Flow Over a Segment Gate
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Spoiler for Wave Improvement at Flow over a Segment Gate CAROLINE LINDBERG Master of Science Thesis Stockholm, Sweden 2013 Spoiler for Wave Improvement at Flow over a Segment Gate Caroline Lindberg Master of Science Thesis MMK 2013:39 MKN 087 KTH Industrial Engineering and Management Machine Design SE-100 44 STOCKHOLM Examensarbete MMK 2013:39 MKN 087 Vinge för vågförbättring vid flöde över segmentlucka Caroline Lindberg Godkänt Examinator Handledare 2013-06-13 Ulf Sellgren Ulf Sellgren Uppdragsgivare Kontaktperson Tikab Strukturmekanik AB Per Stribeck Sammanfattning Tikab Strukturmekanik AB, (Tikab), ett teknikkonsultföretag, har utvecklat en systemhandling för en ny sluss till ”nya Slussen” i Stockholm på uppdrag av Stockholm stad, Exploateringskontoret. En del i projektet var att även skapa attraktiva bonusfunktioner till anläggningen. Innan detta projekt startades hade Tikab visat att den konstruerade segmentluckan kunde användas för att skapa stående vågor nedströms luckan. Dessa vågor ansågs vara intressanta för vågsurfing. Målet med detta examensarbete var att utveckla en konstruktion utan rörliga delar som skulle kunna förbättra vågparametrar hos den, med avseende på surfing attraktiva, genererade vågen. Konstruktionen, också kallad vingen eller spoilern, skulle vara manuellt hanterbar och enkel att montera på slussluckan. Denna rapport beskriver utvecklingsprojektet. Efter att studerat slussen och existerande artificiella surfvågor kunde en omfattande studie av flödesteori göras. Därefter kunde teorier för flöde och vågor användas i modellförsök där de verifierades hydrodynamiskt. Spoilerkoncept togs fram och testades innan en slutlig design kunde väljas genom utvärdering av testresultaten. Det vinnande konceptet konstruerades i full skala och dimensionerades i enlighet med gällande eurokoder. Den slutgiltiga systemkonstruktionen utgjordes av en vinge uppbyggd av sex delar. De kan tillverkas av bockad aluminiumplåt med påsvetsade avstyvningar och ansluts med skruvförband till segmentluckans krön. Genom successiva optimeringar i konstruktionen kunde den totala vikten till slut reduceras till 138 kg, med en maximal vikt på 29 kg för den största delen. Vissa slutsatser drogs utifrån resultaten; Vågformen nedströms en, under vatten, nedsänkt segmentlucka kunde kontrolleras med hjälp av en skruvansluten vinge monterad på luckans krön. Därigenom kunde en attraktiv surfvåg skapas. Den bästa vågförbättringen, med avseende på surfing, uppnåddes för en horisontellt riktad vinge. Vingens form skulle för bästa inverkan vara likformad med den önskade krökningen på vågkrönet. En hanterbar och styv vinge kunde konstrueras med hjälp av aluminiumplåt och en optimerad dimensionering. Nyckelord: segmentlucka, sluss, surfing, vågor, spoiler i ii Master of Science Thesis MMK 2013:39 MKN 087 Spoiler for Wave Improvement at Flow over a Segment Gate Caroline Lindberg Approved Examiner Supervisor 2013-06-13 Ulf Sellgren Ulf Sellgren Commissioner Contact person Tikab Strukturmekanik AB Per Stribeck Abstract Tikab Strukturmekanik AB (Tikab), an engineering consulting company, has developed a system design of a new navigation lock at Slussen in central Stockholm on behalf of Stockholm City authorities. A part of the project has been to add attractive bonus functions to the area. It was shown by Tikab that the designed segment gate, also referred to as Tainter gate, could be used to create stationary back water waves. These waves were found to be of interest for wave surfing. The aim of this master project was to develop a device without moving parts which could improve the wave parameters into an, with respect to surfing, attractive wave. The device, also referred as spoiler, was requested to be manually manageable and easy to mount on the segment gate crest. This master thesis describes the development project. After a study of the navigation lock and existing artificial surf-wave techniques an extensive investigation of flow theory was done. From there theories for flow and wave creation could be transferred into model tests where hydrodynamic verifications were done. Spoiler concepts were developed and tested before a final design was selected by evaluation of the test results. The winning concept was designed in full- scale and dimensioned according to current Eurocodes. The final design was a spoiler which was built up by six parts. They were made for manufacturing using bent and stiffened aluminium plates and to be fastened on the gate crest by bolted joints. Through successive design optimisation, the total weight was reduced to a total of 138 kg. The weight of the largest part was 29 kg. Some conclusions were drawn from the results; The wave shape downstream a submerged segment gate could be controlled by a spoiler on the gate crest. Thereby an attractive wave could be generated. The best wave improvement, with respect to surfing, was reached for a horizontally positioned spoiler cut in a shape equal to the wished wave crest curvature. A manageable and functional spoiler could be designed by the use of aluminium plates and an optimised design. Keywords: segment gate, navigation lock, surf, waves, spoiler iii iv FOREWORD This master thesis project has been carried out at Tikab Strukturmekanik in Danderyd during the spring of 2013. Additionally tests have been carried out at Vattenfall Research and Development in Älvkarleby. I would like to thank those who have being involved during my work on this thesis. First of all, I would like to thank Per-Anders Jönsson and Per Stribeck at Tikab Strukturmekanik for giving me the opportunity to do my master thesis project within a very interesting development project. I would like to thank my industrial supervisor Per Stribeck for guidance, support and patience for my endless questions. Additionally thanks to Claes Holmqvist who has been a great help during model tests and discussions regarding the design process and especially surfing. I would also like to thank the rest at Tikab for support and help when I have needed it. Additionally my thanks go out to Bengt Engwall for building my gate prototype. I would also like to thank personnel at Vattenfall, and especially Mats Billstein, for their helpfulness and interest in my project. At KTH, I would like to thank Hans Bergh, for taking the time to discuss flow processes and different water discharge scenarios, and Ulf Olofsson, for discussions about the test method. Finally I would like to thank Ulf Sellgren, my supervisor and examiner at KTH, for helpful tutoring and discussions. Caroline Lindberg Danderyd, June 2013 v vi NOMENCLATURE The nomenclature is a collection of used symbols, abbreviations and acronyms, with following description, used within this master thesis. Index i is used when notation uses different indexes throughout the documentation, exact definitions are found in respective section. Original and model are stated were needed for differentiating of use. Notations Symbol Description 2 Maximum opening area of opening below gate, original [m ] Width of spoiler part, original [m] Channel width, original and model [m] Width of gate crest in flow direction, original [m] Water depth in Mälaren and Saltsjön, model [m] Weir coefficient used in HEC-RAS [-] Discharge coefficient for underflow [-] Height of gate crest above channel bottom, original [m] Height of gate crest above test trough bottom, model [m] Young’s modulus [Pa] Material strength [Pa] Point load [N] Froude number [-] 2 Gravitational acceleration [m/s ] Height of gate’s rotation axis above channel bottom, original [m] Upstream water surface level above gate crest [m] Channel bottom below RH00, original [m] Downstream water surface level below gate crest, original [m] Upstream resp. Downstream water depth, original [m] Flow dependent quotient [-] Model specific distances [m] Length in original and model [m] Bending moment [Nm] Distributed load [N/m] 3 Flow, original and model [m /s] Radius to gate crest’s system point, original and model [m] Reaction force [N] vii Utilization, applied load compared to load capacity [-] Flow speed [m/s] 3 Volume [m ] Shear force [N] 3 Section modulus [m ] Water surface level for Mälaren resp. Saltsjön, RH00 system, original [m] , Coordinates for model’s hinge relative original’s rotation axis [m] Gate angle at maximum opening below gate [°] Angular distance between gate crest and system line [°] Deflection [m] Spoiler angle [°] Scale factor [-] Discharge coefficient for overflow [-] Relative opening angle in the opening below the gate [-] 3 Density [kg/m ] Local buckling factor Gate angle, original and model [°] Arc length [°] Slope of wave [m] Abbreviations HEC Hydrologic Engineering Center LC Load Case PCL PolyCaprolactone RH00 Swedish ordnance datum system, originating from 1886-1905 Glossary Datum Plane Altitude reference level Locking The procedure going through in a navigation lock (slussning) Nappe The plate of water over-topping a dam Ordnance datum The vertical datum used for deriving altitudes Orifice Opening in a wall designed for water flow/discharge Weir Flow changing barrier across river (överfallsdamm) Submerged weir Barrier below downstream water surface level (grunddamm) viii TABLE OF CONTENTS 1 INTRODUCTION 1 1.1 Background 1 1.2 Purpose 1 1.3 Delimitations 1 1.4 Method 2 2 FRAME OF REFERENCE 3 2.1 Surf Waves 3 2.2 Design of Slussen’s Segment Gate 6 2.3 Hydrodynamics 8 3 DESIGN PROCESS 13 3.1 Geometry of Hydrodynamic Model 13 3.2 Flow at Segment Gate 15 3.3 Scale Model Development 20 3.4 Test Method and Results 23 3.5 Full Scale Spoiler Concept 32 3.6 Dimensioning 34 3.7 Full Scale System Design 45 4 RESULTS 49 4.1 Results 49 5 DISCUSSION AND CONCLUSIONS 51 5.1 Discussion 51 5.2 Conclusions 52 6 FUTURE WORK 53 6.1 Future work 53 7 REFERENCES 55 ix APPENDIX A: HYDRAULIC JUMP APPENDIX B: TEST INPUT APPENDIX C: REJECTED SCALE MODEL CONCEPTS APPENDIX D: SPOILER CONCEPTS APPENDIX E: SPOILER TEST APPENDIX F: MEASURED WAVE DATA APPENDIX G: STRUCTURAL ANALYSIS RESULTS APPENDIX H: BOLTED JOINT APPENDIX I: STEEL DIMENSIONING APPENDIX J: RISK ASSESSMENT x 1 INTRODUCTION The introduction chapter presents background, purpose and delimitations for this master project. The chapter also describes methods that were used in the project.