In this chapter, we focus on some simple cases in which analytical treatments of the Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instabilities can be carried out. This requires neglecting many physical effects and assuming small amplitude perturbations of a single wavelength. The linear stage growth rates are loosely derived and explored. This treatment requires the introduction of the key fluid equations and the concepts of vorticity, species fractions, and diffusion. Comparison is made to experiments.

Chapter 3 focuses on the control of bluff-body wakes, where a bluff body is generally categorized as one whose length in the flow direction is approximately the same as its height. Such shapes exhibit a wide wake on the scale of the body height, with aerodynamic drag that is dominated by a low-pressure region that forms in the near wake of the body. Bluff body wakes are complex and highly unsteady, involving boundary layer flow separation and multiple shear layer interactions. The control of bluff body aerodynamics has practical implications to airfoils at high angles of attack, aircraft landing gear, ground vehicles, and buildings and structures. Methods of control that key on the wake instabilities are presented.

The primary assumptions and formulations for single-phase flow regimes are reviewed in this chapter. This includes the governing partial differential equations for general fluid dynamics (mass, momentum, energy, and species), equations of state and associated flow regimes, rotational effects and the stream function for incompressible flow, and viscous effects with the Reynolds number, including flow instability mechanisms.

This chapter briefly introduces the application of similarity theory and dimensional analysis in fluid mechanics. The concept of flow similarity is discussed at first to give the readers a brief idea what similarity means. Then some important dimensionless number is listed and discussed, which includes Reynolds number, Mach number, Strouhal number, Froude number, Euler number and Weber number. Next, the governing equations are transformed to a dimensionless form to shows how the dimensionless numbers act in the equations. In the end, some flow examples are provided to show the role of the dimensionless numbers.

In this chapter, viscous flow is discussed in detail. This kind of flow represents the most common flow in daily life and industrial production. Firstly, shearing motion and flow patterns of viscous Fluids is introduced, characteristics of laminar flow and turbulent flow is discussed. Secondly, Prandtl’s boundary-layer theory is introduced and boundary-layer equation is derived from the Navier-Stokes equation through dimensional analysis. Thirdly, some theory and facts for turbulent boundary layer are introduced. Fourthly, some shear flows other than boundary layer flow, such as pipe flow, jets, and wakes are briefly introduced. Boundary layer separation is the most important issue in engineering design, so it is introduced and discussed in a separate section in depth. The two top concerns, namely the flow drag and the flow losses are discussed in a separate section with examples and illustrations. Some further knowledge concerning turbulent flow is briefly discussed in the “expanded knowledge” section, such as the theory of homogeneous isotropic turbulent flow and the numerical computation of turbulent flows.

Illustrated examples are given of marine structures, taken from oil exploitation, floating wind production, and other offshore activities. Important parameters such as the Reynolds number and the Keulegan–Carpenter numbers are introduced and the concepts of large and small (or slender) bodies are defined. The separation between linear and nonlinear wave loads and responses is introduced. Finally a brief outline of the book is given.

The last chapter is devoted to model tests. The basic principles of model testing are first presented, that is the Froude scaling law, and the issued related to the biases in Reynolds number. A review is made of experimental facilities used in ocean engineering, and of the wave generation and absorption principles. Issues related to confinement effects, such as sloshing, seiching, Benjamin-Feir instability, emission of free harmonics, etc., are extensively covered. Recommendations are made on specifications and exploitation of model tests.

This chapter applies to bodies that are small compared to the wave lengths, of dimensions similar or smaller than the wave amplitude. As a result separation cannot be neglected and semi-empirical methods are usually applied to formulate the wave and current loading. The Reynolds number is introduced and the different flow regimes, for a circular cylinder in current, are illustrated. The Morison equation is introduced and applied to the wave loading upon cylinders. Experimental values of the inertia and drag coefficients, vs the Reynolds and Keulegan-Carpenter numbers, are presented. The deficiencies of the Morison equations, in complex flows, are emphasized. Alternatives such as the independent flow-field formulation, or wake models, are introduced. The oscillatory lift force, in steady current, is introduced and the Strouhal number and reduced velocity are defined.

Channels are a vital part of irrigation systems. They are the link between the source of water and the irrigation field. Channels used in irrigation systems can be either erodible or non-erodible, or earthen or lined. Flow in channels is governed by the principles of hydraulics. This chapter discusses rudimentary aspects of hydraulics and the design of open channels.

Pumps are an integral part of many agricultural irrigation systems. A pump is used to lift groundwater to the ground surface, raise water from a lower elevation to a higher elevation, transport water, overcome friction, or generate pressure for the operation of sprinkler and trickle irrigation systems. This chapter discusses rudimentary aspects of pumps and their operation and selection.

A pipe is a closed conduit, and when it runs full its hydraulics is different from the hydraulics of open channels in which the upper surface of flow is exposed to the atmosphere. Pipes or closed conduits are used in sprinkler and drip irrigation systems to carry water from the source of water supply to the individual sprinkler or emitter. Water may be conveyed from a reservoir through a pipeline. These systems are also called pressurized irrigation systems. This chapter reviews the principles of pipeline hydraulics.

The concepts of fluid dynamic and thermodynamic similarity are introduced. The key nondimensional parameters of relevance to radial compressors, such as flow coefficient, work coefficient, pressure coefficient and the blade tip-speed Mach number are explained. The appropriate nondimensional parameters allow the preliminary design of a new machine to be based on features of an existing machine, even one designed for a different size, a different fluid, other flow conditions or rotational speed. Its performance can also be estimated from that of a similar machine, even though it may be larger or smaller. The principle of similarity and the associated nondimensional parameters provide an invaluable aid to the design and testing of all turbomachinery and to the proper understanding of their performance maps and stage characteristics. A good grasp of these is an excellent basis for rationalising compressor performance in different applications. Deviations from similarity in real machines are considered leading to performance corrections for changes in Reynolds number and isentropic exponent.