In the present article, in-flight ice formation on finite wings and air intakes of low-speed aircraft are numerically studied. The approach to the problem involves calculation of the velocity field using a three-dimensional panel method. Using the calculated velocity field, the droplet trajectories and droplet impact locations are computed yielding the droplet collection efficiency distribution. In the next step, convective heat transfer coefficient distributions around the geometries are calculated using a two-dimensional Integral Boundary-Layer Method, which takes surface roughness due to ice accretion into account. A thermodynamic analysis employing the Extended Messinger Method yields the ice growth rates. Integration of these rates over time yields the ice shapes, hence the modified geometry. Predicted ice shapes are compared with experimental shapes reported in the literature and good agreement is observed. Ice shapes around vastly varying geometries including complex shapes are successfully computed. As such, the developed tool may be used for academical purposes or for airworthiness certification efforts.

A computational study was performed to compare the stress distributions in finite element torsion box models of a box wing structure that result from employing four different wing/end fin joint fixities. All considered wings were trimmed in pitch. The joint fixities refer to the type of attachment that connects the tip of the fore and aft wings to the end fin. Using loads from a vortex lattice tool, the analysis determined the best wing-joint fixity of a statically loaded idealised box wing configuration by comparing the stress distributions resulting from the different wing joints in addition to other essential aerodynamic requirements. Analysis of the wing joint fixity indicates that the rigid joint is the most suitable.

The satellite attitude determination approach based on the Extended Kalman Filter (EKF) has been widely used in many real applications. However, the accuracy of this method largely depends on the fitness of measurement model. We aim to analyse the influence of measurement errors to the accuracy of EKF based attitude determination approach in this paper. The measurement errors, which are divided into structural error and nonstructural error by their influences, are analysed in principle. In the setting of the combination of star sensors and gyros, according to the property of innovation, we employ the technique of correlation test to analyse the influences of different kinds of measurement errors. Experimental results demonstrate the effectiveness of our previous analysis.

The use of the linearised potential model for the analysis of compressible flows is quite widespread, and provides good results for subsonic and supersonic flows. However, the calculation of aerofoils and wings subject to transonic flows requires a non-linear model, such as the transonic small-disturbance (TSD) potential equation. The solution of the problem by a singularity distribution requires singularities over the field, as well as panels on the boundary, characterising the procedure known as field panel method. The present work shows results of calculations of the transonic small-disturbance potential equation for flows without shock waves using the dual reciprocity method (DRM), which permits calculation of integrals only at the boundary of the problem, without the need of field distributions. This approach, compared to the field panel methods, takes considerably less computer time, and shows a significant improvement when compared to results of linear theory without much additional computer time, making this technique adequate to design phases of aircraft. Pressure distribution results show good agreement with other methods found in litterature. The low computational cost of the present method allows us to perform parametric tests and explore the effects of thickness and Mach number on the lift and pitching moment coefficients. A discussion of the physical effect of these parameters on the problem is presented, and the thickness of the aerofoil is shown to increase the lift and change the position of the aerodynamic centre. However, this non-linear effect depends on the precise shape of the thickness distribution.

The potential positive effects of ground proximity on the aerodynamic performance of a wing or aerofoil have long been established, but at transonic speeds the formation of shock waves between the body and the ground plane would have significant consequences. A numerical study of the aerodynamics of an RAE2822 aerofoil section in ground effect flight was conducted at freestream Mach numbers from 0·5 to 0·9, at a range of ground clearances and angles of incidence. It was found that in general the aerofoil’s lifting capability was still improved with decreasing ground clearance up until the point at which a lower surface shock wave formed (most commonly at the lowest clearances). The critical Mach number for the section was reached considerably earlier in ground effect than it would be in freestream, and the buffet boundary was therefore also reached at an earlier stage. The flowfields observed were relatively sensitive to changes in any given variable, and the lower surface shock had a destabilising effect on the pitching characteristics of the wing, indicating that sudden changes in both altitude and attitude would be experienced during sustained transonic flight close to the ground plane. Since ground proximity hastens the lower surface shock formation, no gain in aerodynamic efficiency can be gained by flying in ground effect once that shock is present.