In this study, we investigated the effect of hull dynamics in shallow water on the hydrodynamic performance of rowing shells as well as canoes and kayaks. An approach was developed to generate data in a towing tank using a test rig capable of reproducing realistic speed profiles. The impact of unsteady shallow-water effects on wave-making resistance was examined via experimental measurements on...

Streamlines, contour lines, vector plots, and volume slices (cutting planes) are commonly used for flow visualization. These techniques are sometimes referred to as instantaneous flow visualization techniques because calculations are based on an instant of the flow field in time. Although instantaneous flow visualization techniques are effective for depicting phenomena in steady flows, they som...

This paper analyses the unsteady, two-dimensional stagnation point flow of an incompressible viscous fluid over a flat sheet when the flow is started impulsively from rest and at the same time, the sheet is suddenly stretched in its own plane with a velocity proportional to the distance from the stagnation point. The partial differential equations governing the laminar boundary layer forced con...

Validation simulations are presented for turbulent flow in a staggered tube bank, geometry similar to the lower plenum of a gas-cooled high temperature reactor. Steady 2D RANS results are compared to unsteady 2D RANS results and experiment. The unsteady calculations account for the fact that nonturbulent fluctuations (due to vortex-shedding) are present in the flow. The unsteady computations ar...

Original scientific paper In this work a new approach considering numerical modelling of waterhammer dissipation and attenuation is proposed. The classical Allievi liquid flow model has been extended with the Brunone unsteady friction model which includes separation of the local and convective unsteady friction factor. A widely-adopted approach in solving this model is treatment of the unsteady...

Formulation and verification of unsteady rarefied flow solver based on Boltzmann-ESBGK equations in arbitrary three-dimensional geometries is presented. The solver is based on the finite volume method in physical space and the discrete ordinate method in velocity space with an implicit time discretization. Verification is carried out for an unsteady approach to equilibrium, a steady one-dimensi...

Turbocharging is becoming a key technology for both Spark Ignition (SI) and diesel automotive engines. As regards gasoline engines, turbocharging can help to reduce CO2 emissions when used in conjunction with other technologies, such as engine downsizing, direct injection and variable valve actuation, all managed on the basis of appropriate control strategies. However, the successful applicatio...

An analysis of fluctuations of speech wave, i.e., pitch, amplitude, and waveform, is a subject of growing interest for improvement in the quality of synthesized voice. However, little information with respect to the sound source itself in speech production is available, since it is difficult to measure fluid and acoustic motions within the larynx. The purpose of the present study is to clarify ...

Unsteady helicopter rotor aerodynamics are complicated. This paper reviews some of the fundamentals and newer developments of unsteady helicopter aerodynamics. Rotor flow is beautiful and complex. Visualizing rotor flow allows for an appreciation of the following theories and solution attempts as well as nature’s complexities. The flow through a helicopter rotor with forward motion is shown in ...

Flood routing has many applications in engineering projects and helps designers in understanding the flood flow characteristics in river flows. Floods are taken unsteady flows that vary by time and location. Equations governing unsteady flows in waterways are continuity and momentum equations which in case of one-dimensional flow the Saint-Venant hypothesis is considered. Dynamic wave model as ...