A moving model test method based on stagnation pressure measurements is proposed to measure the train aerodynamic drag coefficient. Because the front tip of a high-speed train has a high pressure area and because a stagnation point occurs in the center of this region, the pressure of the stagnation point is equal to the dynamic pressure of the sensor tube based on the obtained train velocity. T...

In our present research, we focus on the modeling of airflow related to natural disasters, such assand accumulation, with urban form studies. The objective is to find which urban form can promote sand passing andreduce as much as possible stagnation of sand in the building area (streets, alleys, etc.). The urban form design will bediscussed through the simulation of airflow by using Computation...

Laminar stagnation flow, axi-symmetrically yet obliquely impinging on a rotating circular cylinder, as well as its heat transfer is formulated as an exact solution of the Navier-Stokes equations. Rotational velocity of the cylinder is time-dependent while the surface transpiration is uniform and steady. The impinging stream is composed of a rotational axial flow superposed onto irrotational rad...

A numerical study employing discontinuous Galerkin method demonstrating net surface heat reduction for a cylindrical body in Mach 17 hypersonic flow is presented. This application focuses on using sinusoidal dielectric barrier discharge plasma actuators to inject momentum near the stagnation point. A 5 species finite rate air chemistry model completes the picture by analyzing the effect of the ...

Poor air quality causes an estimated 2.6 to 4.4 million premature deaths per year1-3. Hazardous conditions form when meteorological components allow the accumulation of pollutants in the near-surface atmosphere4-8. Global warming-driven changes to atmospheric circulation and the hydrological cycle9-13 are expected to alter the meteorological components that control pollutant build-up and disper...

Depression is a prevalent mental illness in developed countries. In Western medicine, experimental and clinical investigations have demonstrated that depression is associated with the dysregulation of neurotransmitter signaling, and symptoms of depression can be alleviated by therapeutic intervention. However, patients taking antidepressant drugs often experience serious side effects and high r...

The shape of a bypass graft plays an important role on its efficacy. Here, we investigated flow through two vascular graft designs-with and without cuff at the anastomosis. We conducted Digital Particle Image Velocimetry (DPIV) measurements to obtain the flow field information through these vascular grafts. Two pulsatile flow waveforms corresponding to cardiac cycles during the rest and the exc...

This paper conducts experimental tests to study the stagnation behavior the Interacted Multiple Ant Colonies Optimization (IMACO) framework. The idea of different ant colonies use different types of problem dependent heuristics has been proposed as well. The performance of IMACO was demonstrated by comparing it with the Ant Colony System (ACS) the best performing ant algorithm. The computationa...

Restarting GMRES, a linear solver frequently used in numerical schemes, is known to suffer from stagnation. In this paper, a simple strategy is proposed to detect and avoid stagnation, without modifying the standard GMRES code. Numerical tests with the modified GMRES(m), GMRESH(m) procedure, alone and as part of an inexact Newton procedure with several choices for the forcing term, demonstrate ...

We extend Galor and Weil (2000) by including geographical factors in order to show that under some initial conditions, an economy may be locked in Malthusian stagnation and never take off. Specifically, we characterize the set of geographical factors for which this happens, and this way we show how the interplay of the available “land”, its suitability for living, and its degree of isolation, d...