Experiments on the low-speed flow past cones

Calvert, J.R.

doi:10.1017/s002211206700031x

Cited by 101 publications

(48 citation statements)

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“…It was noted above that Calvert (1967a) studied wakes behind cones with axes parallel to the flow direction, apexes directed upstream, and various apex angles. Such wakes were investigated in more detail by Goldburg and Florsheim (1966) who observed wakes behind freely falling cones (with apexes directed downwards) together with wakes behind falling cone-spheres (hemispheres attached to the base of cones).…”

Section: Wakes Behind Spheres and Other Axisymmetric Bodiesmentioning

confidence: 99%

Stability to Finite Disturbances: Energy Method and Landau’s Equation

Yaglom

Frisch

2012

Fluid Mechanics and Its Applications

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The main part of Chap. 2 and the whole of Chap. 3 were devoted to topics of linear stability theory dealing with the evolution of very small flow disturbances satisfying the linearized fluid dynamics equations. In Chap. 2 it was shown that the classical normal-mode method of the linear theory of hydrodynamic stability often leads to results which strongly disagree with experimental data. It was also indicated there that these disagreements are apparently due to nonlinear effects, which make linearization of the equations of motion physically unjustified. In Chap. 3 it was explained that the necessity for consideration of the full nonlinear dynamic equations often follows from the fact that many solutions of the initial-value problems for linearized fluid dynamics equations grow considerably at small and moderate values of the time t even in the cases when the normal-mode analysis shows that these solutions decay asymptotically (i.e. at t → ∞).The nonlinear theory of hydrodynamic stability has achieved a high level of development. Although the theory is still far from being completed, it has elucidated many formerly mysterious properties of fluid flows which are interesting for physicists and important for engineers. There is now an enormous literature on this subject and only a small part of it, dealing with relatively simple flows of incompressible fluids, will be considered in this book. In the present Chapter two topics from the nonlinear stability theory will be discussed: the energy method of stability analysis (short introductory consideration of this method was included in Sect. 3.4 above) and Landau's approach to the weakly nonlinear stability theory which described the initial period of the nonlinear development of flow disturbances.

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Section: Wakes Behind Spheres and Other Axisymmetric Bodiesmentioning

confidence: 99%

Stability to Finite Disturbances: Energy Method and Landau’s Equation

Yaglom

Frisch

2012

Fluid Mechanics and Its Applications

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“…Many authors have studied these flows to investigate the effect of bluff-body geometry on flame stability (Beer and Chiger, 1983;Sivasegaram and Whitelaw, 1987;Durao and Whitelaw, 1978;Witerfeld, 1965;Bradbury, 1976;Calvert, 1967;Davis and Beer, 1971;Chiger and Beer, 1964). Several studies emphasized the effect of confinement on the nonreacting flow behind bluff bodies.…”

Section: Prior Confined Burner Studiesmentioning

confidence: 99%

Effect of Confinement on Bluff-Body Burner Recirculation Zone Characteristics and Flame Stability

Schefer¹,

Namazian²,

Kelly³

et al. 1996

Combustion Science and Technology

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Most practical burners have some form of confinement. Confinement influences flame stability, emissions and heal transfer. Despite its importance in the design of industrial burners, no systematic and detailed fundamental study of flame confinement has been attempted. As a result, a data gap exists in an area important to burner design. To fill this data gap, we have performed a comprehensive test program that included several bluff-body burners, with different confinements and air jet sizes. This paper presents some of the velocity and fuel concentration data, obtained for four Blockage Ratios (BR). The velocity data were obtained by laser Doppler velocimetry and the concentration data were obtained by Raman imaging. The effect of confinement on velocity and concentration fields, and flame stability are analyzed. It is shown that, for the low BR case, recirculation zone characteristics and flame stability are unaffected by confinement. In contrast, confinement increases the recirculation zone size, distributes the fuel over a larger volume and enhances the stability of the high BR flames. To demonstrate a practical application of the data, concentration results are used to predict complex bluff-body flame regimes.

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“…Kim and Morris (2002) presented the numerical simulation of compressible inviscid mean flow pattern of a cone with 608 vertex angle. The results were compared to the experimental data, assessed by Calvert (1967). Sakai (2009) considered truncated cones to evaluate the CFD simulation of the drag performance of supersonic flow with repetitive energy depositions.…”

Section: Introductionmentioning

confidence: 99%

Drag performance of divergent tubular-truncated cones: a shape optimization study

Lotfi

Rad

2011

Int. J. Environ. Sci. Technol.

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The use of more efficient energy consuming devices, which are closely associated with reduction of environmental pollution, has gained significant interest in the recent decades. The reduction of drag coefficient also improves safety and durability of environmental structures subjected to high-velocity fluid flow, and causes the noise and vibration to decrease as well. This paper describes the efficiency improvement in energy management by means of reducing drag coefficient in a practical divergent tubular-truncated cone. Extensive numerical simulations with emphasis on the shape optimization study were performed in order to find minimum drag coefficient for both laminar and turbulent flows (9.41 9 10 2 B Re B 1.882 9 10 7 ) around the mentioned cone. The numerical results were validated with experimental data, obtained by performing tests in an open circuit wind tunnel. The results showed that the minimum drag coefficient of optimum model within the shape modification process, comparable to the value for the primary model in turbulent flow decreased by 69.8% (the maximum discrepancy) at the highest considered Reynolds number of 1.882 9 10 7 . Furthermore, the study of streamwise velocity profile led to more useful result. In this regard, the velocity magnitude inside the inlet span of the primary model, close to the entrance was approximately 1.6 times as great as the free upstream velocity. This is a noticeable result for the use of efficiency important structures in industrial applications.

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Experiments on the low-speed flow past cones

Cited by 101 publications

References 1 publication

Stability to Finite Disturbances: Energy Method and Landau’s Equation

Stability to Finite Disturbances: Energy Method and Landau’s Equation

Effect of Confinement on Bluff-Body Burner Recirculation Zone Characteristics and Flame Stability

Drag performance of divergent tubular-truncated cones: a shape optimization study

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