Grid capacity, reliability, and efficient distribution of power have been major challenges for traditional power grids in the past few years. Reliable and efficient distribution within these power grids will continue to depend on the development of lighter and more efficient sensing units with lower costs in order to measure current and detect failures across the grid. The objective of this paper is to present the development of a miniature piezoelectric-based sensor for AC current measurements in single conductors, which are used in power transmission lines. Additionally presented in this paper are the thermal testing results for the sensor to assess its robustness for various operating temperatures.

In marine environments, sparse in-situ measurements can be used for the estimation of the fluid dynamic field. To make best use of a mobile sensor network in an environment whose dynamics can be described by the Navier-Stokes equations, we developed a framework for data assimilation with motion-constrained underwater vehicles, that takes the physical field properties into account while sampling. Our algorithm uses an ensemble Kalman filter that propagates hundreds of slightly varied coarse fluid dynamic simulations through time. Flow and scalar measurements from the mobile sensors are integrated into all ensemble members. We implemented a model predictive controller to calculate covariance minimizing paths from the estimated flow field and motion primitives of the vehicles, which are affected by a strong current. Thereby, we were able to indirectly track dynamically changing wall temperatures through measurements of flow field variables.

In hybrid computational aeroacoustics, the acoustic computation domain is oftentimes larger than the domain of the flow simulation. Consequently, discontinuities of the source field occur on the acoustic mesh, which can diminish the quality of the results. A common way to handle truncated source fields is spatial windowing. The present work focuses on aeroacoustic approaches that use time derivatives of the incompressible base flow pressure as acoustic source terms and their distinctive character with respect to source domain truncation. Especially for those approaches, a novel alternative to spatial windowing is proposed, which uses a simplified pressure field continuation beyond the source domain. Numerical results display that spatial windowing and simplified pressure field continuation can both treat truncated source fields effectively. The windowing approach is computationally cheaper but exhibits issues for small flow computation domains. The simplified pressure field continuation can overcome these and other issues yielding very good results while adding little computational cost.

No abstract