1 Easy access to video imaging, digital frame grabbing and image processing technology has opened up exciting opportunities in fluid mechanics education. This paper presents several examples of student work, and discusses new curricula based on these new developments. Complex, unsteady flows can now be quantified using multi-dimensional techniques. Image sequences can be stored and used in prob...

We prove analytic criteria for the existence of finite-time attracting and repelling material surfaces and lines in threedimensional unsteady flows. The longest lived such structures define coherent structures in a Lagrangian sense. Our existence criteria involve the invariants of the velocity gradient tensor along fluid trajectories. An alternative approach to coherent structures is shown to l...

This paper presents an adjoint method for the optimum shape design of unsteady three-dimensional viscous flows. The goal is to develop a set of discrete unsteady adjoint equations and the corresponding boundary condition for the non-linear frequency domain method. First, this paper presents the complete formulation of the time dependent optimal design problem. Second, we present the non-linear ...

We study the effects of the axial component of the shear stress on unsteady pipeline flows. We show that the axial component of the shear stress should be introduced in the modeling of unsteady flows, and as a numerical model, we propose a one-dimensional momentum equation in which a term containing the second derivative of the velocity with respect to space is introduced. The momentum equation...

Solid rocket motor flows depend strongly on alumina granulometry, which spreads up with coalescence. Solving droplet sizes in unsteady flows is a modeling and numerical challenge, specially when high loadings generate retrocoupling. As an alternative to Lagrangian approaches, the Eulerian Multi-Fluid model describes polydispersity with size-sorted droplet fluids called sections. A two size mome...

Solid rocket motor flows depend strongly on alumina granulometry, which spreads up with coalescence. Solving droplet sizes in unsteady flows is a modeling and numerical challenge, specially when high loadings generate retrocoupling. As an alternative to Lagrangian approaches, the Eulerian Multi-Fluid model describes polydispersity with size-sorted droplet fluids called sections. A two size mome...

We propose a new technique to visualize dense vector fields associated with unsteady fluid flows. This technique is based on a Lagrangian-Eulerian Advection (LEA) scheme, and it enables animations with high spatio-temporal correlation at interactive rates. We demonstrate the efficiency and efficacy of the technique in applications to numerical simulation of a shock interacting with a longitudin...

the effect of weak shear thickening and shear thinning on the stability of the taylor-couette flow is explored for a carreau-bird fluid in the narrow-gap limit. the galerkin projection method is used to derive a low-order dynamical system from the conservation of mass and momentum equations. in comparison with the newtonian system, the present equations include additional nonlinear coupling in ...

The effects of unsteady bubble dynamics on cavitating flow through a converging-diverging nozzle are investigated numerically. A continuum model that couples the Rayleigh–Plesset equation with the continuity and momentum equations is used to formulate unsteady, quasi-one-dimensional partial differential equations. Flow regimes studied include those where steady-state solutions exist, and those ...

In this paper the characteristics of unsteady three-dimensional incompressible flows with heat transfer are obtained along with artificial compressibility of Chorin. At first, compatibility equations and pseudo characteristics for three-dimensional flows are derived from five governing equations (continuity equation, Momentum equations in three directions, and energy equation) and then results ...