Two modular side channel pump models have been investigated both numerically and experimentally. For both modular designs, different side channels and impellers could be studied, with the aim to get information about the influence of the different geometries on the performance and the inner flow phenomena of the pump. By understanding the geometry influences, statements about the design process of the pump are possible. Changes of the geometry of the side channel or the impeller affect the flow in both components. This means that the geometrical dimensions must always be related to each other, in order to make statements about influences of the geometry on the characteristics. Thus, various geometrical configurations are setup, their sizes in industrial pumps are indicated and their influence is investigated by simulations. To evaluate the gained numerical data, it is important to understand the influence of mesh and simulation setup on the results. Therefore, a grid study was conducted and additionally the turbulence model was varied. In this paper, two parameters are focused on: these are the side channel height to the blade length (h/l) and the depth of the side channel in relation to the width of the blade (t/w).

Tandem blades can be superior to single blades, particularly when large turning angles are required. This is well documented in the open literature and many investigations have been performed on the 2D-flow of tandem cascades to date. However, much less information on the flow near the sidewalls is available. Thus, the question arises as to how the geometry of a tandem cascade should be chosen near the sidewall in order to minimize the flow losses for large turning angles. The present work examines the 3D-flow field in the region of the sidewall of two high turning tandem cascades. A large spacing ratio was chosen for the forward blade of the first tandem cascade ($(t/l)1=1.92$). The second tandem cascade possessed a smaller spacing ratio for the forward blades ($(t/l)1=1.0$). Both cascades had the same total spacing ratio of $t/l=0.6$. Flow phenomena, such as the corner stall of the 3D boundary layer near the sidewall, are examined using both numerical and experimental methods. The empirical correlations of Lieblein and Lei are applied. The flow topology of both tandem cascades is explained and the locations of loss onset are identified. In addition, oil pictures from experiments and streamline pictures of the numerical simulations are shown and discussed for the flow close to the sidewalls. Finally, design rules such as the aerodynamic load splitting and the spacing ratio of the forward- and aft-blades, etc. are taken into account. The examinations are performed for tandem cascades designed for flow turning of approximately $50 deg$ at a Reynolds number of $8×105$. The tandem cascades consist of NACA65 blades with circular camber lines and an aspect ratio of $b/l=1.0$.

In struggles for cultural leadership, advocating a paradigm helps to disseminate, for example, a style of life, thinking, or common practices. Promoting a practice, that is, branding it, includes the use of a simple name or symbol (semiotic sign). Within geosciences, the label “geoethics” refers to a school of thought that uses established philosophical concepts to promote responsible professional practices. The outcomes that are available aggregate to a more general paradigm that calls for geocentric human practices. The label geoethics also sounds like a brand for those practices. As analysis shows, the notion of geoethics is not univocal. At first sight, that feature hinders using it as a brand for geocentric practices. However, the successful branding of the concept of sustainability, as a scientific and public paradigm, indicates the opposite. Although the notion of sustainability aggregates various concepts and is not univocal, it illustrates what cultural leadership can be achieved when a concept, paradigm, and brand use the same semiotic sign (name). Therefore, it is suggested that the school of thought, Geoethics, with its dedicated reference to the specific societal use of geosciences, should also be used as a brand: geoethics, the general application of geoethical thinking to promote geocentric human practices.

For side channel machines, distinction is made between side channel pumps and peripheral pumps. The blade number of side channel machines has a large influence on the performance of the pump. This is known from several experimental studies. For industrial side channel pumps, the blade number is between 20 and 26, whereas for industrial peripheral pumps, the blade number is much larger (between 36 and 90). In this paper, the influence of the blade number on the performance and the inner flow phenomena of different pumps will be investigated experimentally and numerically. The inner flow of the pump is examined in detail by computational fluid dynamics (CFD) simulations. Flow angles and velocities of the circulation flow between side channel and impeller are considered for different blade numbers. To explain the influences of the blade number, numerical results and theoretical formulas are combined. The experiments are carried out for two different modular side channel pump units, which differ in the side channel height h, the outer impeller diameter da, and the length of the blades l. So, the influence of the blade number can be studied in the context of other parameters like, for example, the relation between blade length and outer diameter of the pump. The obtained numerical results are compared with experimental data. Effects of the blade number on the performance curves of the pumps are shown by experimental and numerical results.

Over the last few decades, several grid coupling techniques for hierarchically refined Cartesian grids have been developed to provide the possibility of varying mesh resolution in lattice Boltzmann methods. The proposed schemes can be roughly categorized based on the individual grid transition interface layout they are adapted to, namely cell-vertex or cell-centered approaches, as well as a combination of both. It stands to reason that the specific properties of each of these grid-coupling algorithms influence the stability and accuracy of the numerical scheme. Consequently, this naturally leads to a curiosity regarding the extent to which this is the case. The present study compares three established grid-coupling techniques regarding their stability ranges by conducting a series of numerical experiments for a square duct flow, including various collision models. Furthermore the hybrid-recursive regularized collision model, originally introduced for cell-vertex algorithms with co-located coarse and fine grid nodes, has been adapted to cell-centered and combined methods.