The Pontydian Performance:the performative layer

In this paper we reflect on the performer-instrument relationship by turning towards the thinking practices of the French philosopher Maurice Merleau-Ponty (1908-1961). Merleau-Ponty's phenomenological idea of the body as being at the centre of the world highlights an embodied position in the world and bestows significance onto the body as a whole, onto the body as a lived body. In order to better understand this two-way relationship of instrument and performer, we introduce the notion of the performative layer, which emerges through strategies for dealing with discontinuities, breakdowns and the unexpected in network performance.

Dramaturgy in the Network

This article addresses challenges and opportunities posed by the design and production of network performance from the point of view of collaborative creative work. It examines strategies that, while referring to the network as a new medium for performance, make use of concepts from dramaturgy to better understand the relationships between artists, audiences and media. The author characterises three distinct models for dramaturgy, particularly from the point of view of collaboration, authorship, presence and environment.

Notating the Unpredictable

Notation can be seen to sit comfortably between theory and practice as it symbolizes practice, generates and implements theory, and produces practice. Historically, its presence changes in significance across the development of activities such as music or architecture. From design tool to canonic text, notational artefacts both solidify and formalize practice, as will be expanded below. How, then, does the role and function of notation change with specific contemporary practices, which are by definition ill-defined and feed off fluidity and change? What is the nature of notation in distributed and collaborative practices such as improvised music or network music performance?

Transonic Aeroelastic Stability Predictions Under the Influence of Structural Variability

Flutter prediction as currently practiced is almost always deterministic in nature, based on a single structural model that is assumed to represent a fleet of aircraft. However, it is also recognized that there can be significant structural variability, even for different flights of the same aircraft. The safety factor used for flutter clearance is in part meant to account for this variability. Simulation tools can, however, represent the consequences of structural variability in the flutter predictions, providing extra information that could be useful in planning physical tests and assessing risk. The main problem arising for this type of calculation when using high-fidelity tools based on computational fluid dynamics is the computational cost. The current paper uses an eigenvalue-based stability method together with Euler-level aerodynamics and different methods for propagating structural variability to stability predictions. The propagation methods are Monte Carlo, perturbation, and interval analysis. The feasibility of this type of analysis is demonstrated. Results are presented for the Goland wing and a generic fighter configuration.

Validation study for prediction of iced aerofoil aerodynamics

Ice accretions can significantly change the aerodynamic performance of wings and rotor blades. Significant performance degradation can occur when ice accreations cause regions of separated flow, to predict this change implies, at a minimum, the solution of the Reynolds-Averaged Navier-Stokes equations. This paper presents validation for two generic cases involving the flow over aerofoil sections with added synthetic ice shapes. Results were obtained for two aerofoils, namely the NACA 23012 and a generic multi-element configuration. These results are compared with force and pressure coefficient measurements obtained in the NASA LTPT wind-tunnel for the NACA 23012, and force, PIV and boundary-layer measurements obtained at DNW for the multi-clement case. The level of agreement is assessed in the context of industrial requirements.

Framework for Establishing Limits of Tabular Aerodynamic Models for Flight Dynamics Analysis

This paper describes the use of the Euler equations for the generation and testing of tabular aerodynamic models for flight dynamics analysis. Maneuvers for the AGARD Standard Dynamics Model sharp leading-edge wind-tunnel geometry are considered as a test case. Wind-tunnel data is first used to validate the prediction of static and dynamic coefficients at both low and high angles, featuring complex vortical flow, with good agreement obtained at low to moderate angles of attack. Then the generation of aerodynamic tables is described based on a data fusion approach. Time-optimal maneuvers are generated based on these tables, including level flight trim, pull-ups at constant and varying incidence, and level and 90 degrees turns. The maneuver definition includes the aircraft states and also the control deflections to achieve the motion. The main point of the paper is then to assess the validity of the aerodynamic tables which were used to define the maneuvers. This is done by replaying them, including the control surface motions, through the time accurate computational fluid dynamics code. The resulting forces and moments are compared with the tabular values to assess the presence of inadequately modeled dynamic or unsteady effects. The agreement between the tables and the replay is demonstrated for slow maneuvers. Increasing rate maneuvers show discrepancies which are ascribed to vortical flow hysteresis at the higher rate motions. The framework is suitable for application to more complex viscous flow models, and is powerful for the assessment of the validity of aerodynamics models of the type currently used for studies of flight dynamics.