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An experimental investigation of hemispherical forebody interaction effects on the drag coefficient of a D-shaped model is carried out for three-dimensional flow in the subcritical range of Reynolds number 1 × 10⁵ ≤ Re ≤ 1.8 × 10⁵. To study the interaction effect, hemispherical shapes of various sizes are attached to the upriver of the D-shaped bluff body model. The diameter of the hemisphere (b₁) varied from 0.25 to 0.75 times the diameter of the D-shaped model (b₂) and its gap from the D-shaped model (g/b₂) ranged from 0.25 to 1.75 b₂.

The experiments were carried out in a low-speed open-circuit closed jet wind tunnel with test section dimensions of 1.2 × 0.9 × 1.8 m (W × H × L) capable of generating maximum velocity up to 45 m/s. The wind tunnel is equipped with a driving unit which has a 175-hp motor with three propellers controlled by a 160-kW inverter drive. Drag force is measured with an internal six-component balance with the help of the Spider 3013 E-pro data acquisition system.

The wind tunnel results show that the hemispherical forebody has a diameter ratio of 0.75 with a gap ratio of 0.25, resulting in a maximum drag reduction of 67%.

The turbulence intensity of the wind tunnel is about 5.6% at a velocity of 18 m/s. The uncertainty in the velocity and the drag coefficient measurement are about ±1.5 and ±2.83 %, respectively. The maximum error in the geometric model is about ±1.33 %.

The results from the research work are helpful in choosing the optimum spacing of road vehicles, especially truck–trailer and launch vehicle applications.

Drag reduction of road vehicle resulting less fuel consumption as well as less pollution to the environment. For instance, tractor trailer experiencing approximately 45% of aerodynamics drag is due to front part of the vehicle. The other contributors are 30% due to trailer base and 25% is due to under body flow. Nearly 65% of energy was spent to overcome the aerodynamic drag, when the vehicle is traveling at the average of 70 kmph (Seifert 2008 and Doyle 2008).

The benefits of placing the forebody in front of the main body will have a strong influence on reducing fuel consumption.

For flow around elongated bluff bodies, flow separations would occur over both leading and trailing edges. Interactions between these two separations can be established through acoustic perturbation. In this paper, the flow and the acoustic fields of a D-shaped bluff body (length-to-height ratio L/H = 3.64) are investigated at height-based Reynolds number Re = 23,000 by experimental and numerical methods. The purpose of this paper is to study the acoustic feedback in the interaction of these two separated flows.

The flow field is measured by particle image velocimetry, hotwire velocimetry and surface oil flow visualization. The acoustic field is modeled in two dimensions by direct aeroacoustic simulation, which solves the compressible Navier–Stokes equations. The simulation is validated against the experimental results.

Separations occur at both the leading and the trailing edges. The leading-edge separation point and the reattaching flow oscillate in accordance with the trailing-edge vortex shedding. Significant pressure waves are generated at the trailing edge by the vortex shedding rather than the leading-edge vortices. Pressure-based cross-correlation analysis is conducted to clarify the effect of the pressure waves on the leading-edge flow structures.

The understanding of interactions of separated flows over elongated bluff bodies helps to predict aerodynamic drag, structural vibration and noise in engineering applications, such as the aerodynamics of buildings, bridges and road vehicles.

This paper clarifies the influence of acoustic perturbations in the interaction of separated flows over a D-shaped bluff body. The contribution of the leading- and the trailing-edge vortex in generating acoustic perturbations is investigated as well.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued

A sign of Aylesbury Automation's new policy of moving into multi‐part assembly work is the company's recent completion of three important electrical assembly contracts, one of them using a 12‐station machine and another employing a computer‐controlled X‐Y table.

THE U.S. Air Force recently ordered twenty‐seven C‐97 Strato‐freighters in addition to the thirteen previously ordered, some of which have been delivered. These are the cargo version of the Boeing Aircraft Company's Stratocruiser.

Presents a standard data format for describing and interpolating 3‐D human body shapes from data collected by a 3‐D body scanner. The body data were treated as a series of horizontal cross‐sections. Each cross‐section was described by 16 data points. The 3‐D surface can be calculated by interpolating between these sections. This procedure allowed editing and manipulation of raw scanned data, as well as substantial data reduction. Horizontal cross‐sections of the body were chosen to correspond to particular anatomical surface landmarks, rather than distances from a reference point. Hence, each data element described a particular anatomical location, irrespective of body shape and size. This feature allowed comparison and averaging of 3‐D shapes, greatly enhancing the application of 3‐D scanned data. The standard data format allows 3‐D scanned data to be transferred into CAD/CAM systems for automated garment design and manikin manufacture.

Students have a unique perspective on how learning space design impacts their school experience (Cook-Sather, 2006). As a result, schools need to be intentional about capturing student voice and feedback throughout the design process. For learning environments to be responsive to the needs of students, schools must enact an inclusive, inquiry-based approach to design.

In this chapter, the authors describe the role that student voice played in an inquiry-driven, iterative process of designing and implementing innovative learning environments in the Middle School at Singapore American School. Through sharing three concrete examples of different data collection methodologies and the changes that emerged as a result of the feedback, the authors outline the power of intentionally centering student voice and experience in designing learning environments. School leaders will learn practical tools to use and a roadmap to follow to create a more inclusive, responsive process of learning environment design, whether engaging in small-scale renovations or planning a whole school. While this chapter focuses on applying this inquiry cycle to learning environments, the process described can equally be used to center student voice in other school change initiatives.

Using finite element (FE) method corrects the microstress field resulting from the theory of homogenization in the region of composite in vicinity of the boundary. Obtains the corrected microstress field via an unsmearing procedure based on the known global solution and local peturbation. Analyses two examples: near a free boundary and next to a constrained border. FE models are constructed using both commercial FE code and the authors’ program for homogenization with some interfacing procedures. Shows qualitative results of computations and estimates influence on the microstress description of the local perturbation near the boundary.

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.