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Ebook Introduction to fluid mechanics: Part 2 - Edward J. Shaughnessy

(BQ) Part 2 book "Introduction to fluid mechanics" has contents: Elements of flow visualization and flow structure, governing equations of fluid dynamics, analysis of incompressible flow, flow in pipes and ducts, external flow, open channel flow. | PART 2 D I FFE R E NTIAL ANALYS I S O F FLOW This page intentionally left blank 10 ELEMENTS OF FLOW VISUALIZATION AND FLOW STRUCTURE 10.1 Introduction 10.2 Lagrangian Kinematics 10.2.1 Particle Path, Velocity, Acceleration 10.2.2 Lagrangian Fluid Properties 10.3 The Eulerian–Lagrangian Connection 10.4 Material Lines, Surfaces, and Volumes 10.5 Pathlines and Streaklines 10.6 Streamlines and Streamtubes 10.7 Motion and Deformation 10.8 Velocity Gradient 10.9 Rate of Rotation 10.9.1 Vorticity 10.9.2 Circulation 10.9.3 Irrotational Flow and Velocity Potential 10.10 Rate of Expansion 10.10.1 Dilation 10.10.2 Incompressible Fluid and Incompressible Flow 10.10.3 Streamfunction 10.11 Rate of Shear Deformation 10.12 Summary Problems 10.1 INTRODUCTION Suppose you are assigned to investigate the possibility of dust, mildew, spores, bacteria, and other debris accumulating in a building’s heating, ventilating, and air-conditioning (HVAC) system. This is important because the accumulation of allergens like these may cause respiratory discomfort. Experience suggests that deposits of airborne materials 573 574 10 ELEMENTS OF FLOW VISUALIZATION AND FLOW STRUCTURE occur in regions of slow or recirculating flow, so you are to review the HVAC design and identify any regions in which allergens might accumulate. Now consider the proposed duct layout for an HVAC return line illustrated in Figure 10.1A. Will regions of slow or recirculating flow occur with this layout? Wouldn’t it be nice to be able to “see” the corresponding flow in this duct section so that you could answer the flow question before the ducting was installed? Flow visualization is the tool that can help you with this sort of task. Vents Flow Region of sudden expansion Flow (A) TURBULENT FLOW THROUGH A SUDDEN AXISYMMETRIC EXPANSIO STREAMLINE CONTOUR .