scholarly journals Design Methods for Minimization of Sonic‐Boom Pressure‐Field Disturbances

1965 ◽  
Vol 38 (5) ◽  
pp. 910-910 ◽  
Author(s):  
F. Edward McLean ◽  
Barrett L. Shrout
Keyword(s):  
Pressure Field ◽  
Design Methods ◽  
Sonic Boom

Sonic‐Boom Pressure‐Field Estimation Techniques

1966 ◽  
Vol 39 (5B) ◽  
pp. S10-S18 ◽  
Author(s):  
Harry W. Carlson ◽  
Robert J. Mack ◽  
Odell A. Morris
Keyword(s):  
Pressure Field ◽  
Sonic Boom ◽  
Estimation Techniques ◽  
Field Estimation

Active sonic boom control

1996 ◽  
Vol 325 ◽  
pp. 1-28 ◽  
Author(s):  
Steven C. Crow ◽  
Gene G. Bergmeier
Keyword(s):  
Acoustic Waves ◽  
Pressure Field ◽  
Field Approximation ◽  
Simple Relation ◽  
Sonic Boom ◽  
Simulation Code ◽  
Sonic Booms ◽  
Supersonic Aircraft ◽  
Velocity Changes ◽  
Algebraic Term

A theory and simulation code are developed to study non-steady sources as means to control sonic booms of supersonic aircraft. A key result is that the source of sonic boom pressure is not confined to the length of the aircraft but occupies an extensive segment of the flight path. An aircraft in non-steady flight functions as a synthetic aperture antenna, generating complex acoustic waves with no simple relation to instantaneous volume or lift distributions.The theory applies linear acoustics to slender non-steady sources but requires no far-field approximation. The solution for pressure contains a term not seen in Whitham's theory for sonic booms of distant supersonic aircraft. The term describes a pressure field that decays algebraically behind the Mach cone and, in the case of steady flight, integrates to a ground load equal to the weight of the aircraft. The algebraic term is separate from those that describe the sonic boom.Two non-steady source phenomena are evaluated: periodic velocity changes (surge), and periodic longitudinal lift redistribution (slosh). Surge can attenuate a sonic boom and covert it into prolonged weak reverberation, but accelerations needed to produce the phenomenon seem too large for practical use. Slosh may be practical and can alter sonic booms but does not, on average, result in boom attenuation. The conclusion is that active sonic boom abatement is possible in theory but maybe not practical.

Lift Produced by a Sonic Boom

1963 ◽  
Vol 67 (636) ◽  
pp. 796-796 ◽  
Author(s):  
A. Sigalla
Keyword(s):  
Pressure Field ◽  
Radial Distance ◽  
Wave Pattern ◽  
Technical Note ◽  
Sonic Boom ◽  
Velocity Perturbation ◽  
Flight Direction ◽  
Apparent Inconsistency ◽  
N Wave ◽  
Asymptotic Forms

The Technical Note by C. H. E. Warren in the September Journal raises a question on the transfer of lift, of an aeroplane in supersonic flight, to the ground. This problem was considered in reference 2. It was shown that, as expected, the resultant of the pressure field produced by the aeroplane is equal to its lift. This apparent inconsistency with the N-wave pattern, predicted by Whitham stems from the fact that most applications of Whitham's theory are based on asymptotic forms for the velocity perturbations. Thus, the formula for the axial velocity perturbation is obtained by allowing (M2— l)l/2r/y to tend to infinity, where M is the flight Mach number, r the radial distance away from the aeroplane, y=x—(M2 — l)1/2, and x is the distance along the aeroplane flight direction. This approximation is valid in the vicinity of the shock waves emanating from the aeroplane.

scholarly journals Sonic boom mitigation via shape optimization using an adjoint method and application to a supersonic fighter aircraft

2008 ◽  
pp. 217-243
Author(s):  
Kurt Maute ◽  
Charbel Farhat ◽  
Brian Argrow ◽  
Melike Nikbay
Keyword(s):  
Shape Optimization ◽  
Adjoint Method ◽  
Pressure Field ◽  
Near Field ◽  
Pressure Rise ◽  
Flight Test ◽  
Computational Method ◽  
Sonic Boom ◽  
Fighter Aircraft ◽  
Initial Shock

This paper describes a computational method for the analysis and mitigation via shape optimization of the sonic boom associated with supersonic flight. The method combines a CFD approach for determining the near-field pressure field and an acoustic scheme for predicting the initial shock pressure rise at the ground. Two venues are considered for computing the ground signature. The performance of both approaches is evaluated using flight test data of two different configurations of an F5 fighter aircraft.

scholarly journals Sonic‐Boom Pressure‐Field Estimation Techniques

1965 ◽  
Vol 38 (5) ◽  
pp. 910-910 ◽  
Author(s):  
Harry W. Carlson ◽  
Robert J. Mack ◽  
Odell A. Morris
Keyword(s):  
Pressure Field ◽  
Sonic Boom ◽  
Estimation Techniques ◽  
Field Estimation

Shocks and singularities in the pressure field of a supersonically rotating propeller

1988 ◽  
Vol 192 ◽  
pp. 1-16 ◽  
Author(s):  
C. J. Chapman
Keyword(s):  
Pressure Field ◽  
Nonlinear Effects ◽  
Sonic Boom ◽  
Square Roots ◽  
Shocks And Singularities ◽  
Special Case

When linear acoustic theory is applied to the thickness noise problem of a supersonic propeller, it can give rise to a surface on which the pressure is discontinuous or singular. A method is described for obtaining the equation of this surface (when it exists), and the pressure field nearby; jumps, logarithms and inverse square roots occur, and their coefficients may be calculated exactly. The special case of a blade with a straight radial edge gives a cusped cone, whose sheets, each with a different type of discontinuity or singularity in pressure, are separated by lines of cusps; the coefficients in formulae for the pressure near the surface tend to infinity as a cusp line is approached, in proportion to the inverse quarter power of distance from the line. These results determine regions of space where nonlinear effects are important, and they suggest a strong analogy with sonic boom.

Section 4.a Introduction

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Silvia PIZZOCARO ◽  
Pınar KAYGAN ◽  
HARMAN Kerry ◽  
Erik BOHEMIA
Keyword(s):  
Social Problems ◽  
Elderly Care ◽  
Child Poverty ◽  
Design Methods ◽  
Innovative Solutions ◽  
Design Council

Co-design is a process in which designers and users collaborate as ‘equals’ to develop innovative solutions. Co-design methods are increasingly used by professional designers to facilitate and enable users to co-develop innovative solutions for ‘themselves’. For example, the Design Council is advocating the use of co-design methods to support the development of practical innovative solutions to social problems such as increased cost of elderly care and tackling child poverty. The involvement of users in developing solutions acknowledges that their take up is dependent on the ways users create and negotiate meanings of objects and services.

Design as an Agent for Public Policy Innovation

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Federico VAZ ◽  
Sharon PRENDEVILLE
Keyword(s):  
Public Policy ◽  
Process Model ◽  
Public Policies ◽  
Policy Innovation ◽  
Design Methods ◽  
Policy Effectiveness ◽  
The Public ◽  
Dependent Activity ◽  
Effectiveness And Efficiency ◽  
Context Dependent

Described as units developing public policies in a design-oriented manner, Policy Labs are tasked to innovate to gain in policy effectiveness and efficiency. However, as public policymaking is a context-dependent activity, the way in which these novel organisations operate significantly differs. This study discusses the emergence of design approaches for policy innovation. The purpose is to map how Policy Labs in Europe introduce design approaches at distinct stages of the policymaking cycle. For this study, 30 organisations in Europe operating at various levels of government were surveyed. Based on the public policymaking process model, it investigates which design methods are Policy Labs deploying to innovate public policies. The study exposed a gap in the awareness of the utilised methods' nature. It also showed that the use of design methods is of less importance than the introduction of design mindsets for public policy innovation, namely ‘user-centredness’, ‘co-creation’, and ‘exploration’.

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