A Numerical Study of the Limiting Cases of Cylinder-Induced Shock Wave/Boundary Layer Interactions

One of the limiting factors in the design of supersonic and hypersonic vehicles remains the prediction and control of the high aerodynamic, thermodynamic, acoustic, and structural loads generated by a shock wave/boundary layer interaction (SWBLI or SBLI). In conjunction with an experimental campaign produced within the research group, a numerical study was performed using a semi-infinite cylinder to generate a SWBLI at Mach 1.88 with both laminar and turbulent boundary layers. The goals were not only to better understand the complex flow surrounding the cylinder-induced turbulent interaction, but also to establish the interaction bounds of the limiting cases of a transitional interaction. Steady-state Reynolds-averaged Navier-Stokes (RANS) simulations were performed to predict the shock structures, separation and attachment points, and pressure profiles in the upstream region and on the cylinder leading edge. A variety of turbulence models were tested, namely the cubic k-epsilon (CKE), Menter’s shear-stress transport (SST), and Spalart-Allmaras (SA) with quadratic constitutive relations (QCR). Both the CKE and SA-QCR turbulence models showed good agreement with in-house experimental data and literature, and are thus recommended for future use in these types of flow fields. Correlations between the vortex structures and peak and trough pressures were found, thus allowing for a steady-state flow characterization. The effect of varying the incoming boundary layer height was studied, when all other values were kept constant, and it was determined that an increased boundary layer height decreased both the interaction scale and the peak pressure

EFFECT OF LATERALLY MOVEABLE PEDALS (BIUS) ON KINEMATICS, PEDAL FORCES AND MUSCLE ACTWIN IN RECREATIONAL CYCLING

The purpose of this study was to investigate the effect of a laterally moveable pedal on the kinematics, kinetics and muscle activity in recreational cycling compared to cycling with a standard pedal on an ergometer. Four healthy participants cycled at 100 W and 200 W at 80 rpm with a standard and the BIUS pedal. Kinematics, kinetics and muscle activation have been measured in both conditions. No differences were found regarding the joint angles and in the lateral movement of the pedal. Some differences were partly observed for the ground reaction forces and the muscle activation pattern. In the ergometer setting the BIUS pedal does not lead to kinematic changes of the cycling movement, but causes effects on pedal forces and muscle activation

The language of self-avoiding walks

Let $X=(V\!X,E\!X)$ be an infinite, locally finite, connected graph without loops or multiple edges. We consider the edges to be oriented, and $E\!X$ is equipped with an involution which inverts the orientation. Each oriented edge is labelled by an element of a finite alphabet $\mathbf{\Sigma}$. The labelling is assumed to be deterministic: edges with the same initial (resp. terminal) vertex have distinct labels. Furthermore it is assumed that the group of label-preserving automorphisms of $X$ acts quasi-transitively. For any vertex $o$ of $X$, consider the language of all words over $\mathbf{\Sigma}$ which can be read along self-avoiding walks starting at $o$. We characterize under which conditions on the graph structure this language is regular or context-free. This is the case if and only if the graph has more than one end, and the size of all ends is $1$, or at most $2$, respectively.Comment: 24 pages, 3 figure

Location decisions and the liability of foreignness: Spillover effects between factor market and capital market strategies

In this paper we build on the liability of foreignness concept and the institutional perspective to show how an equity listing and subsidiary formations in the host market are interlinked. Using a matched sample of foreign equity-listed and domestic equity-listed European firms on EU-regulated capital markets, we find that (1) the number of prior host-market subsidiary formations increases the probability of a host-market equity listing, and (2) a prior host-market equity listing increases the number of host-market subsidiary formations. Hence, we identify spillover effects between factor market and capital market strategies. However, the extent of these spillover effects depends on institutional characteristics of the host market, where companies on smaller markets gain higher spillover effects. We contribute to international management and finance research by providing factor market strategies as a valuable source to overcome capital market liabilities of foreignness and capital market strategies as a valuable source to overcome factor market liabilities of foreignness

Position Paper: Escaping Academic Cloudification to Preserve Academic Freedom

Especially since the onset of the COVID-19 pandemic, the use of cloud-based tools and solutions - lead by the ‘Zoomification’ of education, has picked up attention in the EdTech and privacy communities. In this paper, we take a look at the progressing use of cloud-based educational tools, often controlled by only a handful of major corporations. We analyse how this ‘cloudification’ impacts academics’ and students’ privacy and how it influences the handling of privacy by universities and higher education institutions. Furthermore, we take a critical perspective on how this cloudification may not only threaten users’ privacy, but ultimately may also compromise core values like academic freedom: the dependency relationships between universities and corporations could impact curricula, while also threatening what research can be conducted. Finally, we take a perspective on universities’ cloudification in different western regions to identify policy mechanisms and recommendations that can enable universities to preserve their academic independence, without compromising on digitalization and functionality