Engineering Estimates of Normal Loads on Slender Airbreathing Bodies
01 Nov 2004-Journal of Spacecraft and Rockets (American Institute of Aeronautics and Astronautics (AIAA))-Vol. 41, Iss: 6, pp 942-947
TL;DR: In this article, a method is developed to obtain quick engineering estimates for the normal load on slender airbreathing shapes using a Trefftz plane analysis, although two-dimensional and subsonic, agrees fairly well with experimental data (from NASA and AGARD) for three-dimensional slender bodies in supersonic flows.
Abstract: A method is developed to obtain quick engineering estimates for the normal load on slender airbreathing shapes. Estimates of the normal load can be obtained using a Trefftz plane analysis. This computation, although two-dimensional and subsonic, agrees fairly well with experimental data (from NASA and AGARD) for three-dimensional slender bodies in supersonic flows. The computational technique is simple and extremely fast.
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09 Jan 2006
TL;DR: In this article, the applicability of PARAS-3D for the prediction of the external aerodynamics of body-intake configurations and also to find the effect of flow through intakes on external aerodynamic coefficients.
Abstract: Aerodynamic study over body-intake configurations has been carried out using a CFD code, PARAS. Body -Twin Intake and Body-Cruciform Intake configurations were studied. The air- intakes are two-dimensional. Computations were carried out for Mach numbers 2.0 and 3.0, angle of incidence from -10 o to +10 o and roll angles 0 o and 45 o . Computations with and without flow through the intakes were carried out. The CFD results were compared with the experimental data and the agreement is found to be good. The effect of flow through intakes on normal force and pitching moment is not significant where the effect is significant on axial force. 6 and Vipin kumar 7 on body-intake configurations for measurement of external aerodynamic coefficients. The objective of present study is to find the applicability of the CFD code, PARAS-3D for the prediction of the external aerodynamics of body-intake configurations and also to find the effect of flow through intakes on external aerodynamic coefficients. The details of body-intake configurations, PARAS-3D code and the computational results are presented. Comparison of the CFD results with experimental data is also presented. II. Body-intake Configurations Two configurations were investigated. configuration-1 consists of body with two side-mounted intakes (twin intake configuration) and configuration-2 consists of body with four intakes (cruciform intake configuration). The body consists of ogival nose followed by circular cylinder. The body is identical for both configurations. Diameter of the body is 27 mm. Nose fineness ratio is 3 and slenderness ratio of the model is 15. The intakes are 2-dimensional. Length and span of intakes of both configurations is same. Thickness of intakes of twin intake configuration is twice that of intakes of cruciform configuration. For twin intake configuration, intake entry plane is not facing the body. For cruciform intake configuration, intake entry plane is facing the body. Angle of intake entry plane is 34.4° with respect to flow direction for all he intakes. The details of the configurations are shown in Fig.1. In the flow through condition, the thickness of the intake walls is taken as 0.5mm. III. PARAS-3D code PARAS-3D code is a PARallel Aerodynamic Simulator, which can simulate viscous, turbulent and three-dimensional fluid flow over arbitrary three-dimensional bodies. The grid around the bodies is generated by means of a Rectangular Adaptive Cartesian Mesh (RAM) technique. This code is based on explicit scheme with second order accurate in space and of total variation diminishing (TVD) type, which is $
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01 Jan 1991
TL;DR: In this article, the authors present a general solution of the Incompressible, Potential Flow Equations over three-dimensional airfoils, with complex variables. But they do not specify the exact solutions with complex variables.
Abstract: Introduction and Background. Fundamentals of Inviscid, Incompressible Flow. General Solution of the Incompressible, Potential Flow Equations. Small Disturbance Flow Over Three Dimensional Airfoils. Exact Solutions with Complex Variables. Perturbation Methods. Three-Dimensional Small Disturbance Solutions. Numerical (Panel) Methods. Singularity Elements and Influence Coefficients. Two-Dimensional Numerical Solutions. Three-Dimensional Numerical solutions. Unsteady Aerodynamics. Advanced Topics. Airfoil Integrals. Singularity Distribution Integrals. Principle Value of the Lifting Surface Integral. Sample Computer Programs.
612 citations
01 Jan 1979
TL;DR: In this article, the overall aerodynamic drag characteristics of a conventional wheelchair were defined and individual drag contributions of its components were determined, and the results showed that a fiftieth percentile man sitting in the complete wheelchair would experience an aerodynamic Drag coefficient on the order of 1.4.
Abstract: The overall aerodynamic drag characteristics of a conventional wheelchair were defined and the individual drag contributions of its components were determined. The results show that a fiftieth percentile man sitting in the complete wheelchair would experience an aerodynamic drag coefficient on the order of 1.4.
20 citations
TL;DR: The variation, impairment, or extinction of trilling as a function of gradual decrease in intraoral pressure was analyzed acoustically and it was found that voiceless and ejective trills are significantly less affected by venting than fricatives.
Abstract: What are the aerodynamic conditions required for trills? To find out we had two subjects produce steady‐state voiced, voiceless, and ejective alveolar trills. The backpressure during trills was intermittently bled with a tube of varying diameter (and thus impedance) inserted in the speaker’s mouth via the buccal sulcus and gap behind the back molars. Intraoral pressure was measured via a catheter inserted into the pharynx through the nose. The variation, impairment, or extinction of trilling as a function of gradual decrease in intraoral pressure was analyzed acoustically. It was found that (1) bleeding the oro‐pharyngeal pressure by 2 cm H2O impaired sustained trilling; (2) the minimum Po required to sustain tongue‐tip vibration is lower than that required to initiate it; (3) extinction (and reinitiation) of trilling generally results in a fricative; (4) the range of Po variation for trills is narrower than that for fricatives; (5) voiceless and ejective trills are significantly less affected by venting the backpressure than voiced trills. The behavior of trills in varying aerodynamic conditions accounts for observed phonological patterns: final trill devoicing, alternation between trills and fricatives, co‐occurrence of trilling and frication, and limited distribution of trills. [Work supported by DGICYT, Spain, PB 96‐1158, and by Committee on Research, UCB.]
16 citations