Fluid Dynamics Research 

About: Fluid Dynamics Research is an academic journal published by IOP Publishing. The journal publishes majorly in the area(s): Vortex & Reynolds number. It has an ISSN identifier of 0169-5983. Over the lifetime, 1873 publications have been published receiving 31731 citations.

Phenomena of liquid drop impact on solid and liquid surfaces

Abstract: The fluid dynamic phenomena of liquid drop impact are described and reviewed. These phenomena include bouncing, spreading and splashing on solid surfaces, and bouncing, coalescence and splashing on liquid surfaces. Further, cavitation and the entrainment of gas into an impacted liquid may be observed. In order to distinguish properly between the results of different experiments different impact scenarios are discussed. The specific conditions under which the above phenomena did occur in experiments are analyzed and the characteristics of drop impact phenomena are described in detail.

New Insights into Large Eddy Simulation

Abstract: Fluid dynamic turbulence is one of the most challenging computational physics problems because of the extremely wide range of time and space scales involved, the strong nonlinearity of the governing equations, and the many practical and important applications. While most linear fluid instabilities are well understood, the nonlinear interactions among them makes even the relatively simple limit of homogeneous isotropic turbulence difficult to treat physically, mathematically, and computationally. Turbulence is modeled computationally by a two-stage bootstrap process. The first stage, direct numerical simulation, attempts to resolve the relevant physical time and space scales but its application is limited to diffusive flows with a relatively small Reynolds number (Re). Using direct numerical simulation to provide a database, in turn, allows calibration of phenomenological turbulence models for engineering applications. Large eddy simulation incorporates a form of turbulence modeling applicable when the large-scale flows of interest are intrinsically time dependent, thus throwing common statistical models into question. A promising approach to large eddy simulation involves the use of high-resolution monotone computational fluid dynamics algorithms such as flux-corrected transport or the piecewise parabolic method which have intrinsic subgrid turbulence models coupled naturally to the resolved scales in the computed flow. The physical considerations underlying and evidence supporting this monotone integrated large eddy simulation approach are discussed.

A new dynamical framework of nonhydrostatic global model using the icosahedral grid

Abstract: For a nonhydrostatic global model that is run efficiently at super-high resolution, we propose the use of an icosahedral grid, which is one of the quasi-homogeneous grid systems. In this paper, we concentrate mainly on the description of the numerical scheme of a new dynamical framework using the icosahedral grid. The numerical method guarantees conservations of mass and total energy. To reduce the computational cost, the time-splitting scheme is employed and the set of equations is solved explicitly in the horizontal directions and implicitly in the vertical direction. This scheme only requires solving a one-dimensional Helmholtz equation for the vertical momentum. With the combination of this conservative nonhydrostatic scheme and the icosahedral grid, it is expected that the new model will efficiently run for super-high resolution simulations.For the first assessment of the performance of the new dynamical core, we performed fundamental wave propagation tests; acoustic waves, gravity waves, mountain waves, equatorial waves, and planetary waves. In order to check the performance as a climate model, we also performed the Held-Suarez Test Case as a statistical test. As a result, our model result has good correspondence with that of other established models.

Camassa–Holm, Korteweg–de Vries-5 and other asymptotically equivalent equations for shallow water waves

Abstract: We derive the Camassa–Holm equation (CH) as a shallow water wave equation with surface tension in an asymptotic expansion that extends one order beyond the Korteweg–de Vries equation (KdV). We show that CH is asymptotically equivalent to KdV5 (the fifth-order integrable equation in the KdV hierarchy) by using the non-linear/non-local transformations introduced in Kodama (Phys. Lett. A 107 (1985a) 245; Phys. Lett. A 112 (1985b) 193; Phys. Lett. A 123 (1987) 276). We also classify its travelling wave solutions as a function of Bond number by using phase plane analysis. Finally, we discuss the experimental observability of the CH solutions.

Surface wave propagation in mangrove forests

Abstract: Mangroves are a special form of vegetation as they exist at the boundary of terrestrial and marine environment. They have a special role in supporting fisheries and in the stabilizing the tropical coastal zones. Biochemical and trophodynamic processes in the mangroves are strongly linked to water movement, due to tides and waves. In this paper we present the theoretical attempt to predict the attenuation of wind-induced random surface waves in the mangrove forest. The energy dissipation in the frequency domain is determined by treating the mangrove forest as a random media with certain characteristics determined using the geometry of mangrove trunks and their locations. Initial nonlinear governing equations are linearized using the concept of minimalization in the stochastic sense and interactions between mangrove trunks and roots have been introduced through the modification of the drag coefficients. The resulting rate of wave energy attenuation depends strongly on the density of the mangrove forest, diameter of mangrove roots and trunks, and on the spectral characteristics of the incident waves. Examples of numerical calculations as well as preliminary results from observation of wave attenuation through mangrove forests at Townsville (Australia) and Iriomote Island (Japan) are given.