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Article
Publication date: 14 July 2022

Velmani M. and Suresh V.

This paper aims to numerically investigate the influence of shock wave and freestream turbulence interaction on the parabolic and spherically blunted nose cones at…

Abstract

Purpose

This paper aims to numerically investigate the influence of shock wave and freestream turbulence interaction on the parabolic and spherically blunted nose cones at supersonic speed.

Design/methodology/approach

Using density-based solver, the three-dimensional steady-state simulation is carried out. The working fluid is calorically perfect that obeys ideal gas law and the no-slip boundary conditionis given to the surface of the nose cone. Pressure far-field boundary condition is imposed at the boundary of the computational domain by giving freestream Mach number, freestream static pressure and temperature.

Findings

The growth rate of the boundary layer is faster on the spherically blunted nose cone, hence, the overall drag force is higher than the parabolic nose cone. Temperature at the edge of the boundary layer is increased due to the early ampli-fication of instabilities by the upstream disturbance. In this sense, the effects of freestream turbulence depend on its level, freestream conditions, strength and type of shock wave and zone of influence.

Research limitations/implications

Simulations are carried out for the flow Mach number 2.0 at zero angles of attack for the freestream conditions of the flow at an altitude of 10,000 m.

Practical implications

The phenomenon of shock wave–turbulence interaction occurs in flow regimes from transonic to hypersonic speeds and finds a wide range of applications, especially in the design of aircraft and missiles configurations.

Originality/value

The phenomenon of compression wave and freestream turbulence interaction around the commonly used nose cones in the case of aircraft, missiles, etc., is investigated. The performance characteristics such as aerodynamic drag, boundary layer dynamics and the nature of flow around the different nose cones at zero angle of attack are illustrated.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 2 October 2017

Xuzhao He, Jialing Le and Si Qin

Waverider has high lift to drag ratio and will be an idea aerodynamic configuration for hypersonic vehicles. But a structure permitting aerodynamic like waverider is still…

Abstract

Purpose

Waverider has high lift to drag ratio and will be an idea aerodynamic configuration for hypersonic vehicles. But a structure permitting aerodynamic like waverider is still difficult to generate under airframe’s geometric constrains using traditional waverider design methods. And furthermore, traditional waverider’s aerodynamic compression ability cannot be easily adjusted to satisfy the inlet entrance requirements for hypersonic air-breathing vehicles. The purpose of this paper is to present a new method named osculating general curved cone (OCC) method aimed to improve the shortcomings of traditional waveriders.

Design/methodology/approach

A basic curved cone is, first, designed by the method of characteristics. Then the waverider’s inlet captured curve and front captured tube are defined in the waverider’s exit plane. Osculating planes are generated along the inlet captured curve and the designed curved cone is transformed to the osculating planes. Streamlines are traced in the transformed curved cone flow field. Combining all streamlines which have been obtained, OCC waverider’s compression surface is generated. Waverider’s upper surface uses the free stream surface.

Findings

It is found that OCC waverider has good volumetric characteristics and good flow compression abilities compared with the traditional osculating cone (OC) waverider. The volume of OCC waverider is 25 per cent larger than OC waverider at the same design condition. Furthermore, OCC waverider can compress incoming flow to required flow conditions with high total pressure recovery in the waverider’s exit plane. The flow uniformity in the waverider exit plane is quite well.

Practical implications

The analyzed results show that the OCC waverider can be a practical high performance airframe/forebody for hypersonic vehicles. Furthermore, this novel waverider design method can be used to design a structure permitting aerodynamic like waverider for a practical hypersonic vehicle.

Originality/value

The paper puts forward a novel waverider design method which can improve the waverider’s volumetric characteristics and compression abilities compared with the traditional waverider design methods. This novel design approach can extend the waverider’s applications for designing hypersonic vehicles.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 6 December 2018

Xiaojing Wang, Hao Liu and Guojia Man

Aiming at the cavitations and noise problem of hydraulic cone valve and based on the radial force analysis of the valve core, the radial deviation of the spool is…

Abstract

Purpose

Aiming at the cavitations and noise problem of hydraulic cone valve and based on the radial force analysis of the valve core, the radial deviation of the spool is considered to obtain the changing rules of cavitations and noise.

Design/methodology/approach

The solid model of the internal flow field of cone valve is established. The mesh models are divided using ICEM-CFD software. The numerical simulation of the liquid-gas two-phase flow is performed on the cavitation and noise of the flow field inside the cone valve based on FLUENT software. The visible experimental platform for cavitation and noise of hydraulic cone valve is built. According to the contrast of the experimental results, the correctness of the simulation results is verified.

Findings

The results show that the radial deviation causes the position of the cavitation accumulates in the valve cavity on the side of the upper cone. In addition, the strength of the cavitation changes slowly with the half cone angle of 45°, and the noise level is the smallest. Furthermore, appropriately increasing the opening degree within a reasonable range can effectively suppress cavitation and reduce the noise level.

Originality/value

The cavitation can be suppressed and the noise level can be reduced by means of changing the three factors, which lays the foundation for the design and theoretical research of the cone valve.

Details

Industrial Lubrication and Tribology, vol. 71 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 3 May 2013

Li Fu, Lingling Wang and Jianghai Hu

The aim of this paper is to propose a new coning correction algorithm, based on the singular perturbation technique, for the attitude update computation with non‐ideal…

Abstract

Purpose

The aim of this paper is to propose a new coning correction algorithm, based on the singular perturbation technique, for the attitude update computation with non‐ideal angular rate information.

Design/methodology/approach

Unlike conventional coning correction algorithms, the new method uses angular rate two‐time scale model to construct the coning correction term of attitude update. In order to achieve balanced real/pseudo coning correction performance, the selection guidelines of the new algorithm parameters are established.

Findings

Performance of the new algorithm is evaluated by comparison with the conventional algorithm in no ideal sensors undergoing stochastic coning environments. The accuracy of attitude update can be improved effectively with reduced computational workload by using this new coning algorithm as compared with conventional ones.

Practical implications

The proposed coning correction algorithm can be implemented with angular rate sensors in UAV (unmanned aerial vehicle) and other aircrafts attitude estimation for navigation and control applications.

Originality/value

Singular perturbation is an effective method for structuring coning correction algorithm with filtered angular rate outputs in stochastic coning environments. The improved coning correction algorithm based on singular perturbations reduces the real and pseudo coning effects effectively as compared with conventional ones. It is proved to be valid for improvement of accuracy with reduced computations of the attitude update.

Details

Aircraft Engineering and Aerospace Technology, vol. 85 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 4 January 2016

Qian Li, Wei Gao and Jiubin Tan

The purpose of this paper is to justify the algorithm optimization based on a consideration of its accuracy characteristics in a pure coning motion, which is widely used…

Abstract

Purpose

The purpose of this paper is to justify the algorithm optimization based on a consideration of its accuracy characteristics in a pure coning motion, which is widely used in optimizing strapdown attitude algorithms to describe the special angular motion of a vehicle.

Design/methodology/approach

Two more general angular motions of a vehicle were given: generalized vibration describing periodical motions and benign dynamic describing aperiodical motions. The algorithm performances were evaluated in these two motions.

Findings

The theoretical analysis and numerical results show that errors of the algorithm optimized in pure coning motion are null or neglectable in these two motions, and performance of the optimized algorithm in a pure coning motion is superior to that of the non-optimized algorithm.

Originality/value

The value of the paper lies in that the authors justify the concept optimizing strapdown attitude algorithms in a pure coning motion.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 88 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 August 2001

P.E. Dijk, A.M.C. Janse, J.A.M. Kuipers and W.P.M. van Swaaij

The average residence time of liquid flowing over the surface of a rotating cone was determined numerically. The development and propagation of the free surface flow was…

Abstract

The average residence time of liquid flowing over the surface of a rotating cone was determined numerically. The development and propagation of the free surface flow was simulated using the volume of fluid (VOF) method. The numerical simulations were validated using laboratory experiments using soy‐oil as a model liquid, and approximate analytical solutions of the simplified governing equations. The numerical simulations revealed the importance of the cone rotation frequencies and the minor influence of the cone angles on the residence times. Higher liquid throughputs produced smaller residence times. As expected, an increasing cone size results in proportionally higher residence times. Furthermore, it was established that even for small cones with a characteristic diameter of, e.g. less than 1m, relatively high (∼1 kg/s) throughputs of liquid are possible. It appears that the combination of the decreasing layer thickness and the increasing size of the numerical grid cells with increasing radial cone coordinate hampers the numerical simulation of this system.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 11 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 26 September 2019

Zhiguo Tang, Hai Li, Feng Zhang, Xiaoteng Min and Jianping Cheng

The purpose of this paper is to explore the flow and heat transfer characteristics of the jet impingement onto a conical heat sink and evaluate the ability of heat…

Abstract

Purpose

The purpose of this paper is to explore the flow and heat transfer characteristics of the jet impingement onto a conical heat sink and evaluate the ability of heat transfer enhancement.

Design/methodology/approach

A numerical study of the flow and heat transfer of liquid impingement on cone heat sinks was conducted, and transition SST turbulence model was validated and adopted. The flow and thermal performances were investigated with the Reynolds number that ranges from 5,000 to 23,000 and cone angle that ranges from 0° to 70° in four regions.

Findings

Local Nusselt numbers are large, and pressure coefficients drop rapidly near the stagnation point. In the conical bottom edge, a secondary inclined jet was observed, thereby introducing a horseshoe vortex that causes drastic fluctuations in the curves of the flow and heat transfer. The average Nusselt numbers are higher in a conical protuberance than in flat plates in most cases, thus indicating that the heat transfer performance of jet impingement can be improved by a cone heat sink. The maximum increase is 13.6 per cent when the cone angle is 60°, and the Reynolds number is 23,000.

Originality/value

The flow and heat transfer behavior at the bottom edge of the cone heat sink is supplemented. The average heat transfer capacity of different heat transfer radii was evaluated, which provided a basis for the study of cone arrays.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 11
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 13 November 2017

Bikash Routh, Rathindranath Maiti and Asok Kumar Ray

In a harmonic drive during assembly of its components like strain wave generating (SWG) cam, flexspline (FS) and circular spline, a gap is formed between the cam’s outer…

Abstract

Purpose

In a harmonic drive during assembly of its components like strain wave generating (SWG) cam, flexspline (FS) and circular spline, a gap is formed between the cam’s outer surface and the FS cup inner surface due to mismatching. This gap, which is known as “Coning”, plays a vital role in the flow of lubricant at that interface. This paper aims to analyse the coning phenomenon and the lubrication mechanism.

Design/methodology/approach

In the present investigation, the geometry of the coning gap and its variation with the SWG cam rotation are established. Essentially, the deflection of FS cup and deformation of SWG cam (bearing outer race) are derived to find the gap due to coning. Next, the hydrodynamic lubrication equation is solved to get pressure profiles for this gap under suitable boundary conditions assuming non-Newtonian lubrication.

Findings

Methods of estimating the coning gap and lubrication pressure profiles are established. Effects of non-Newtonian terms (coupling number and non-dimentionalized characteristic length) and SWG length (finite, long and short) on pressure profiles are also shown. All analyses are done in non-dimensionalized form.

Originality/value

Establishing the geometry of coning and non-Newtonian hydrodynamic lubrication aspects in the coning in the FS cup and SWG cam interface are the originality of the present investigation.

Details

Industrial Lubrication and Tribology, vol. 69 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 27 May 2014

F.O. Pătrulescu, T. Groşan and I. Pop

The purpose of this paper is to investigate the steady mixed convection boundary layer flow from a vertical frustum of a cone in water-based nanofluids. The problem is…

Abstract

Purpose

The purpose of this paper is to investigate the steady mixed convection boundary layer flow from a vertical frustum of a cone in water-based nanofluids. The problem is formulated to incorporate three kinds of nanoparticles: copper, alumina and titanium oxide. The working fluid is chosen as water with the Prandtl number of 6.2. The mathematical model used for the nanofluid incorporates the particle volume fraction parameter, the effective viscosity and the effective thermal diffusivity. The entire regime of the mixed convection includes the mixed convection parameter, which is positive for the assisting flow (heated surface of the frustum cone) and negative for the opposing flow (cooled surface of the frustum cone), respectively.

Design/methodology/approach

The transformed non-linear partial differential equations are solved numerically for some values of the governing parameters. The derivatives with respect to? were discretized using the first order upwind finite differences and the resulting ordinary differential equations with respect to? were solved using bvp4c routine from Matlab. The absolute error tolerance in bvp4c was 1e-9.

Findings

The features of the flow and heat transfer characteristics for different values of the governing parameters are analysed and discussed. The effects of the particle volume fraction parameter \phi, the mixed convection parameter \lambda and the dimensionless coordinate? on the flow and heat transfer characteristics are determined only for the Cu nanoparticles. It is found that dual solutions exist for the case of opposing flows. The range of the mixed convection parameter for which the solution exists increases in the presence of the nanofluids.

Originality/value

The paper models the mixed convection from a vertical truncated cone using the boundary layer approximation. Multiple (dual) solutions for the flow reversals are obtained and the range of existence of the solutions was found. Particular cases for ?=0 (full cone), ? >>1 and (free convection limit) \lambda>>1were studied. To the authors best knowledge this problem has not been studied before and the results are new and original.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 11 January 2016

John Hamilton and Singwhat Tee

Four learning modes, interacting through students as different learning systems, are mapped into a cone-of-learning continuum that allows tertiary institutions to visually…

1256

Abstract

Purpose

Four learning modes, interacting through students as different learning systems, are mapped into a cone-of-learning continuum that allows tertiary institutions to visually re-consider where within their cone-of-learning, they choose to position their learning approaches. Two forms of blended learning are also distinguished. The paper aims to discuss these issues.

Design/methodology/approach

Undergraduate law, business, IT, and creative arts student perceptions are structural equation modelled (SEM) into traditional, blended-enabled, blended-enhanced, and flexible learning systems.

Findings

Within the SEM derived learning cone-of-learning continuum, a migration from traditional learning systems towards blended and flexible learning systems typically offers higher-net levels of undergraduate student learning experiences and outcomes.

Research limitations/implications

The authors do not capture learning system feedback loops, but the cone-of-learning approaches can position against chosen competitors. The authors recognise benchmark, positioning, and transferability differences may exist between different tertiary institutions; different learning areas; and different countries of operation. Cone-of-learning studies can expand to capture student perceptions of their value acquisitions, overall satisfaction, plus trust, and loyalty considerations.

Practical implications

The cone-of-learning shows shifts towards flexibility as generating higher student learning experiences, higher student learning outcomes, and as flexible technologies mature this demands higher student inputs. These interactive experiential systems approaches can readily incorporate new technologies, gamifications, and engagements which are testable for additional student deep-learning contributions. Experiential deep-learning systems also have wide industrial applications.

Social implications

Understanding the continuum of transitioning between and across deeper-learning systems offers general social benefit.

Originality/value

Learning system studies remain complex, variable systems, dependent on instructors, students, and their shared experiential engagements environments. This cone-of-learning continuum approach is useful for educators, business, and societal life-long learners who seek to gauge learning and outcomes.

Details

The TQM Journal, vol. 28 no. 1
Type: Research Article
ISSN: 1754-2731

Keywords

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