1 Introduction to Complex Problems in Fluids Engineering 1.1 Background Knowledge 1.2 Strategies for Treating Complex Flows 1.2.1 Fundamental Flow Features 1.2.2 Common Methods for Treating Flow Issues 1.3 Characteristics of Flow Problems 1.3.1 Flow Quantities 1.3.2 Unsteadiness 1.3.3 Symmetry 1.3.4 Stability 1.3.5 Symmetry,Intermittency and Periodicity 1.3.6 Phase Change 1.3.7 Flows in an Integrated System References 2 A Brief Overview of Research Methods 2.1 Introduction of Experiment 2.1.1 Definition of Experiment 2.1.2 Experimental Instruments 2.1.3 Fidelity of Experiment 2.2 Numerical Methods for Flows 2.2.1 Governing Equations 2.2.2 Turbulence Model 2.2.3 Turbulent Characteristics 2.2.4 Cavitation Model 2.2.5 Other Issues 2.3 Some Limitations of CFD 2.4 Structural Analysis References 3 Submerged Waterjet 3.1 Fundamental Features of Submerged Waterjet 3.1.1 Experimental Set-Up 3.1.2 Average Flow Characteristics of Submerged Waterjet 3.1.3 Vorticity Distribution and Pressure Fluctuation 3.1.4 Cavitation 3.2 Submerged Waterjet Issued at Ultra-High Jet Pressures 3.2.1 Cavitation Erosion Mechanism 3.2.2 Experimental Methods and Rig 3.2.3 Results and Analysis 3.2.4 Summary 3.3 Cavitation Simulation for Submerged Waterjet and Experimental Validation 3.3.1 Numerical Model and Procedure 3.3.2 Discussion of Numerical Results 3.3.3 Cavitation Prediction 3.3.4 Experimental Setup 3.3.5 Experimental Results 3.4 Concluding Remarks References 4 Motion of Bubble 4.1 Rising Bubble in Stationar} Water 4.1.1 Experimental Set-Up and Image-Processing Code 4.1.2 Experimental Results and Analysis 4.1.3 Summary 4.2 Bubbles Released in Horizontal Water Flow 4.2.1 Experimental Preparations 4.2.2 Results and Discussion 4.2.3 Bubble Deformation and Dimensionless Numbers 4.2.4 Summary References 5 Wake Flow of the Ventilation Cylinder 5.1 Experimental Setup 5.1.1 Water Tunnel and Ventilated Cylinder 5.1.2 Optical Configuration 5.1.3 Bubbles Separation Algorithm 5.2 Velocity and Vorticity Distributions 5.3 Bubbles Size Prediction 5.3.1 Bubbly Flow Patterns 5.3.2 Bubble Size 5.3.3 Comparison of Bubble Size Distribution 5.4 Bubble Velocity Distribution 5.5 Statistical Features of Bubble Volume 5.6 Concluding Remarks References 6 Drag-Type Hydraulic Rotor 6.1 Introduction 6.2 Experimental Setup 6.2.1 Drag-Type Hydraulic Rotor 6.2.2 Test Segment of the Water Tunnel 6.2.3 PIV Set-Up 6.3 Flow Patterns Near the Hydraulic Rotor 6.3.1 Wake Flow Patterns 6.3.2 Flow Characteristics Near the Rotor 6.3.3 Vorticity Distribution 6.4 Numerical Preparations 6.4.1 Governing Equations and Turbulence Model 6.4.2 Grid Deployment Scheme 6.4.3 Boundary Conditions 6.5 Validation of Numerical Simulation 6.6 Variation of Torque Coefficient with Rotor Rotation References 7 Viscous Flows in the Impeller Pump 7.1 Introduction 7.2 Pump Structure and Parameters 7.3 Numerical Preparations 7.3.1 Governing Equations and Turbulence Model 7.3.2 Boundary Conditions 7.3.3 Verification of Numerical Settings 7.4 Results and Discussion 7.4.1 Pump Performance 7.4.2 Flow Patterns 7.4.3 Pressure Fluctuations 7.5 Hydraulic Forces Exerted on Impeller Blades 7.6 Concluding Remarks References 8 Cavitation in the Condensate Pump 8.1 Introduction 8.2 Cavitation Feature of the Centrifugal Pump 8.3 Modification of Impeller Geometry 8.4 Pump Performance Experiment 8.5 Numerical Preparations 8.5.1 Governing Equations,Turbulence Model and Cavitation Model 8.5.2 Grid Deployment Scheme 8.5.3 Boundary Conditions 8.5.4 Validation of the Computational Scheme 8.6 Numerical Results and Discussion 8.6.1 Geometric Features of Cavitation 8.6.2 Effect of Flow Rate on Cavitation at NPSHa=3.0 m 8.6.3 Effect of NPSHa on Cavitation at Design Flow Rate 8.7 Conclusions References 9 Structural Aspect of the Impeller Pump 9.1 Flow-Structure Interaction in the Molten Salt Pump 9.1.1 A Brief Introduction of the Molten-Salt Pump 9.1.2 Numerical Set-Up for Flow Simulation 9.1.3 Flow Characteristics of the Pump 9.1.4 Numerical Setup for Structural Calculation 9.1.5 Temperature Distribution in the Rotor 9.1.6 Strength Analysis of the Rotor 9.1.7 Modal Analysis 9.1.8 Summary 9.2 Structural Improvement of a Condensate Pump 9.2.1 Overview of the Condensate Pump 9.2.2 Condensate Pump and Vibration Description 9.2.3 Flow Simulation for the Pump 9.2.4 Motor Test 9.2.5 Modal Analysis of the Original Pump Base 9.2.6 Improvement of Motor Supporting References