A review of aerodynamic aspects of ram wing research

Theoretical and experimental research into the aerodynamics of ram wings is reviewed. The theories of two-dimensional and finite wings in ground effect are discussed and mention is made of the various experimental techniques available for ground effect tests. The possible shortcomings of each method are noted. In the final section it is concluded that there is a considerable need for research into the dynamic stability of ram wings. It is suggested that any dynamic tests should include measurements of the effect of the movement of the ground, as might be experienced when in transit. over a wavy sea

Aero-Structural Design Optimization of Adaptive Shock Control Bumps

Shock control bumps (SCB) are a transonic flow control device that aim to reduce the overall drag due to a normal shock on a typical passenger jet at cruise. The concept of adaptive SCB which can be deployed for best use are investigated through an aero-structural design tool that produces optimal geometries. The optimizer uses a surface based performance metric to highlight the importance of the flow quality around the SCB as well as including a structural element that is required to provide the necessary flexibility to deform. The performance metric produces the target pressure distribution and successfully smears the shock. It is found that the structural constraint does not inhibit bump height and global airfoil performance is not significantly a↵ected, L/D varies < 0.6%. The aerodynamic pressure loading can be utilised to produce a new family of SCB geometries that are unachievable with mechanical actuation alone. The study shows that adaptive SCB that exploit the naturally occurring pressure field around an airfoil in a passive way are a feasible technology to mitigate the poor o↵-design performance of static SCB

Transonic Airfoil Study Using Sonic Plateau, Optimization and Off-Design Performance Maps

A number of transonic airfoils, designed using differing approaches, are evaluated over a wide range of operating conditions, using a tool for generating aerodynamic performance maps. Details of key performance boundaries are also extracted, including drag divergence and separation onset. The aerodynamic performance maps and boundaries, which are based upon extensive use of a rapid 2D CFD tool, are first demonstrated on an existing airfoil, for which the design condition is known and for which experimental data is available. Aerodynamic maps are then presented for a series of airfoils which are designed using a sonic plateau, inverse design approach. Further maps are presented for airfoils designed using single-point and multi-point optimization. The impact of the alternative design approaches is studied, using the performance maps and the resulting characteristics of the performance boundaries. In particular, the trade-off between drag divergence and the onset of separation, combined with viscous and wave drag development, is presented. The study provides some insights into the challenge of achieving a well posed optimization formulation for transonic airfoil design

Consumer perceptions of co-branding alliances: Organizational dissimilarity signals and brand fit

This study explores how consumers evaluate co-branding alliances between dissimilar partner firms. Customers are well aware that different firms are behind a co-branded product and observe the partner firms’ characteristics. Drawing on signaling theory, we assert that consumers use organizational characteristics as signals in their assessment of brand fit and for their purchasing decisions. Some organizational signals are beyond the control of the co-branding partners or at least they cannot alter them on short notice. We use a quasi-experimental design and test how co-branding partner dissimilarity affects brand fit perception. The results show that co-branding partner dissimilarity in terms of firm size, industry scope, and country-of-origin image negatively affects brand fit perception. Firm age dissimilarity does not exert significant influence. Because brand fit generally fosters a benevolent consumer attitude towards a co-branding alliance, the findings suggest that high partner dissimilarity may reduce overall co-branding alliance performance

An exploratory study of the determinants of the quality of strategic decision implementation in Turkish industrial firms

This paper investigates the determinants of quality of decision implementation. By drawing on a sample of 116 firms located in Turkey, the authors test whether the features of important team processes (i.e. trust and participation), of the organisation (i.e. past performance) and of implementation (i.e. its speed and uncertainty) exert an influence on the quality with which decisions are implemented. Exploratory and confirmatory factor analyses were used to test the validity of the measures, while path analysis was used in hypotheses testing. The results suggest that quality of decision implementation is positively related to trust, participation and past performance, and negatively to implementation speed and uncertainty. The implications of these findings for theory, practice and general management are discussed