This paper investigates the effect of turbulence models on numerical simulation of the vortical flow over a wingbody configuration at low speed and high angles of attack. Numerical simulations are conducted using Reynolds-Averaged Navier-Stokes equations with three popular turbulence models: the Spalart-Allmaras model, the Menter's shear stress transport model, and the Launder-Sharma k-" model. Computational results are compared with experiments. The original Spalart-Allmaras model shows excessively large dissipation in the vortical flow away from the surface, but the rotation correction indicates significant improvement in computational results. The Menter's model predicts reasonable agreement with the experiment in details and capture vortex structures well. The Launder-Sharma k-" model performs provides results close to those of the Menter's model at high angles of attack. Although details of the flowfield have been simulated with large differences by different turbulence models, the choice of turbulence models is not important for prediction of aerodynamic forces.

In this study, the accuracy of structured and unstructured mesh CFD codes in simulating the flow around a threeelement high-lift configuration (slat, main wing, and flap) is assessed, and mesh dependency and effect of turbulence models are studied. In the first part of the study, the results of two structured mesh CFD codes and an unstructured mesh CFD code using the same turbulence model are compared and discussed. A mesh refinement approach is also used to examine the dependency of numerical accuracy on the density of unstructured meshes. By properly distributing mesh points in an unstructured mesh, the detail in flow physics is obtained. It is also shown that the quantitative prediction of the vortex in the slat cove is an important factor that affects accuracy. In the second part of the study, three turbulence models are compared using one of the structured mesh CFD codes. All turbulence models can produce similar flowfields. However, several differences are seen in the separated regions, especially in the slat cove. Commonly used turbulence models, Spalart-Allmaras model and Menter's SST model, produce similar aerodynamic forces at lower angles of attack. At higher angles of attack, the SST model gives better results for the present computations. It is found that the maximum lift and the angle at which the stall occurs are very sensitive to the turbulence model.

Support of network mobility (NEMO) in nextgeneration wireless systems requires an effective handover scheme optimized specially for NEMO. Conventional NEMO basic support protocol brings high handover latency, which is unacceptable for the real-time services such as VoIP. And other node mobility schemes are not quite suitable for NEMO. In this paper, we propose, and evaluate a fast handover scheme for supporting NEMO in IEEE 802.16e BWA networks. The results of the evaluation show that our scheme has much lower handover latency than NEMO basic support protocol. It also only involves few modifications in network entities and works well with other schemes, which support node mobility.

Ambulatory arterial stiffness index (AASI) is a novel estimate of arterial stiffness which independently predicts cardiovascular mortality, even in normotensive subjects. Additionally, other markers derived from ambulatory blood pressure (BP) monitoring, including variability (BPV), pulse pressure (PP), nocturnal dipping, and morning BP surge have all been shown to be predictive of endorgan damage and cardiovascular disease. Exaggerated cardiovascular reactivity to sympathoexcitatory stimuli may also predict future incidence of hypertension. The purpose of this investigation was to test the hypothesis that AASI and other derivations of ambulatory BP, including PP, 24-hr BPV, dipping, and morning surge, would be correlated with the pressor response to common physiological stress maneuvers. We measured continuous HR and arterial BP during headup tilt, mental stress, cold pressor test, and isometric handgrip to fatigue in 67 healthy, normotensive, non-obese individuals (43 women, 24 men, mean age ± SD: 28 ± 6 yr). Then 24-hr ambulatory BP was obtained, and AASI was defined as 1 minus the slope of diastolic on systolic BP in individual 24-h ambulatory BP recordings. Although all measures were widely variable among subjects, there was no relationship between AASI, PP, BPV, dipping, and morning surge with the pressor responses. We conclude that in the absence of aging, cardiovascular, or autonomic disease, the novel stiffness index (AASI) or other ambulatory BP indices are either poorly correlated with, or mechanistically unrelated to the complex pressor response to common provocations of sympathoexcitation.

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