L'effet de la taille et du fluide actif sur la conception multi-objectifs des compresseurs centrifuges à grande vitesse

The impact of size and working fluid on the efficiency, operating range, and axial thrust on bearings is examined for high-speed, oil-free centrifugal compressors. First, the development and validation of a reduced-order model based on scaling principles is documented. Then, the validated compressor model is used to generate design maps for...

CFD code comparison, verification and validation for decay tests of a FOWT semi-submersible floater

With the advancement of high-performance computation capabilities in recent years, high-fidelity modelling tools such as computational fluid dynamics are becoming increasingly popular in the offshore renewable sector. To justify the credibility of the numerical simulations, thorough verification and validation is essential. In this work,...

Recent advances in understanding the flow over bluff bodies with different geometries at moderate Reynolds numbers

The application of unsteady incompressible flow phenomenon over the bluff bodies has received the attention of many researchers due to the rich and complex physics underpinning these flows, and thus requiring special attention in their modelling and numerical simulations. The wake that forms at the leeside of the bluff body is of particular...

Data-driven optimization of building-integrated ducted openings for wind energy harvesting: Sensitivity analysis of metamodels

Metamodels are developed and used for aerodynamic optimization of a ducted opening integrated into a high-rise building to maximize the amplification factor within the duct. The duct consists of a nozzle, a throat, and a diffuser. 211 high-resolution 3D RANS CFD simulations are performed to generate training and testing datasets. The space...

Modeling the hydraulic excavation of cohesive soil by a moving vertical jet

In dredging, high pressure water jets are commonly applied to assist the mobilization of soil. This work considers the excavation of cohesive soil. The key objective is to predict the development of the cavity in the soil as a function of the undrained shear strength, translation velocity and hydrodynamic pressure of a single nozzle. A...

Impacts of shearing and temperature on sewage sludge: Rheological characterisation and integration to flow assessment

Accurate rheological characterisation of sewage waste activated sludge (WAS) is of high importance for downstream processing related to optimised sludge pumping and mixing, assessment of energy demands and overall process design. However, to elaborate rheological behaviour is often challenging under dynamic operational conditions in practice....

Influence of inland vessel stern shape aspects on propulsive performance: Derivation of insights and guidelines based on a computational study

This research focuses on identifying the most important stern shape aspects, with regard to resistance and propulsion power, of inland ships. Such information should help designers to determine which hull form aspect to adjust in case design requirements need them to do so. The information is obtained by firstly conducting a large series of CFD...

Modelling uncertainty in t-RANS simulations of thermally stratified forest canopy flows for wind energy studies

The flow over densely forested terrain under neutral and non-neutral conditions is considered using commercially available computational fluid dynamics (CFD) software. Results are validated against data from a site in Northeastern France. It is shown that the effects of both neutral and stable atmospheric stratifications can be modelled...

Dust Emission Modeling around a Stockpile by Using Computational Fluid Dynamics and Discrete Element Method