A recent focus in studies of vortex shedding behind circular cylinders has been on the use of low-order dynamical systems such as circle maps to predict wake dynamics. These purely temporal models have been limited by their inability to describe three-dimensional spatial flow variations along the cylinder span, a hallmark of transitional flows such as the cylinder wake. In the present work this...

A highly accurate Fourier-Chebyshev spectral collocation method has been used to simulate flow in the wake of a sphere in the Reynolds number range from 350 to 650. Flow visualizations and frequency spectra provide a glimpse of the complex vortex dynamics that are observed in the sphere wake. It is found that in addition to the vortex shedding frequency which corresponds to the shedding of larg...

In many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. For any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. The failure will happen in the equipment, when this frequency is close to...

Local scouring in the downstream of hydraulic structures is one of the important issues in river and hydraulic engineering, which involves a lot of costs every year, so the prediction of the rate of scour is important in hydraulic design. Side weirs are the most important of hydraulic structures that are used in passing flow. This study investigate the scouring due to falling jet from side weir...

A computational inquiry focuses on leading-edge vortex LEV growth and shedding during acceleration of a two-dimensional flat plate at a fixed 10°–60° angle of attack and low Reynolds number. The plate accelerates from rest with a velocity given by a power of time ranging from 0 to 5. During the initial LEV growth, subtraction of the added mass lift from the computed lift reveals an LEV-induced ...

The classical problem of suppressing vortex shedding in the wake of a circular cylinder by using body rotation is revisited in an adjoint-based optimal control framework. The cylinder’s unsteady and fully unconstrained rotation rate is optimized at Reynolds numbers between 75 and 200 and over horizons that are longer than in previous studies, where they are typically of the order of a vortex sh...

Vortex shedding may occur in tube arrays, resulting in strong excitation forces at discrete frequencies. In the past the Strouhal numbers governing vortex shedding in these systems were determined primarily by experiment. This paper presents a computationally inexpensive method of numerical simulation for the unsteady flow through a rigid normal triangular tube array which determines both the f...

This paper considers the turbulent-flow characteristics and the mechanism of vortex shedding behind one and two square obstacles centered inside a 2-D channel. The investigation was carried out for a range of Reynolds number (Re) from 1 to 300 with a fixed blockage ratio β = 0.25. Comparison of the flow patterns for the single and two obstacles was feasible. The computations were based on the f...

The generation of vortices for the flow past a flat plate is calculated by the DSMC method. The new intermolecular collision scheme and the conventional one are compared with respect to their allowable cell dimension. In the condition of Re=50, when using the conventional scheme, the vortex behind an inclined flat plate becomes weak with increasing the cell dimension beyond the mean free path, ...