scholarly journals Rapid thermalization by adaptive flow reorientation

2021 ◽  
Vol 2116 (1) ◽  
pp. 012114
Author(s):  
R Lensvelt ◽  
M F M Speetjens ◽  
H Nijmeijer

Abstract Aim of this paper is the enhancement of scalar transport (heat, chemical species) in flow systems with reorientations of a laminar base flow. Conventional heating/mixing protocols comprise of temporal or spatial periodic reorientations of these base flows to promote fluid mixing. However, thermal homogenisation rates of scalar fields are not necessarily accelerated with these approaches due to the substantial effect of diffusion and/or chemical reactions on heat/chemical transport. In the present study we numerically study heat transport with an adaptive approach for an entire parameter space of fluid and flow properties. Key to the approach is real-time control of the fluid flow based on the scalar field due to an efficient numerical model. Results show that the adaptive approach can significantly enhance heat transport over the conventional periodic heating/mixing approach designed for efficient mixing.

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
D. M Unwin ◽  
A. J Saul

Water industries worldwide are becoming increasingly interested, due to the recent improvements in the devices, methodologies and tools available, in the development and utilisation of Real Time Monitoring/Control (RT-M/C) applications. The University of Sheffield Pennine Water Group is currently researching the development of RT-M/C solutions for wastewater systems and the minimisation of urban flooding impact within the United Kingdom. These solutions are being developed, utilising quasi-steady state methodology, by the combining and utilisation of data, from both a novel laboratory scale prototype research apparatus, as shown in Figure 1, and theoretical mathematical analysis/Computational Fluid Dynamics (CFD). Figure 1 Figure 1. The project will ultimately centre on the development of a suite of RT- M/C algorithms/Flood Risk decision support tools (FRDST), which can be applied, with confidence to real world applications. Initial phases of the project centred on the development of the laboratory facility, and the enhancement of current system understanding in terms of hydraulic functionality, and its impact upon the transportation of soluble pollutants. This impact upon pollutant transportation has been quantified (by laboratory experimentation) in terms of the ‘dominating’ (backwater) effects of converging dry weather (type) and storm (type) flows due to the presence of a (simple) sewer manhole junction. These dominating effects are hypothesised to be due to the combined parameters of angle of inlet (of dry weather/base flows), the magnitude of the base flow rate and the ratio of the base flow rate to the joining storm flow rate. The effect upon pollution (mass) transportation has been shown to mirror the magnitude of the backwater effects, thus allowing the hypothesis, that hydraulic effects alone should form the foundation of any subsequent development of RT-M/C algorithms/FRDST. Further to this it is also hypothesised that the resulting model could confidently be applied to systems understanding/control in terms of hydraulic performance in general, and the minimising (through adopted DST) of flood risk at key sewer system junctions. Particularly in terms of environmental protection schemes and cost minimising strategies.


1995 ◽  
Vol 34 (05) ◽  
pp. 475-488
Author(s):  
B. Seroussi ◽  
J. F. Boisvieux ◽  
V. Morice

Abstract:The monitoring and treatment of patients in a care unit is a complex task in which even the most experienced clinicians can make errors. A hemato-oncology department in which patients undergo chemotherapy asked for a computerized system able to provide intelligent and continuous support in this task. One issue in building such a system is the definition of a control architecture able to manage, in real time, a treatment plan containing prescriptions and protocols in which temporal constraints are expressed in various ways, that is, which supervises the treatment, including controlling the timely execution of prescriptions and suggesting modifications to the plan according to the patient’s evolving condition. The system to solve these issues, called SEPIA, has to manage the dynamic, processes involved in patient care. Its role is to generate, in real time, commands for the patient’s care (execution of tests, administration of drugs) from a plan, and to monitor the patient’s state so that it may propose actions updating the plan. The necessity of an explicit time representation is shown. We propose using a linear time structure towards the past, with precise and absolute dates, open towards the future, and with imprecise and relative dates. Temporal relative scales are introduced to facilitate knowledge representation and access.


2007 ◽  
Vol 73 (12) ◽  
pp. 1369-1374
Author(s):  
Hiromi SATO ◽  
Yuichiro MORIKUNI ◽  
Kiyotaka KATO

Author(s):  
Vladimir V. NEKRASOV

Developing a microcontroller-based system for controlling the flywheel motor of high-dynamics spacecraft using Russian-made parts and components made it possible to make statement of the problem of searching control function for a preset rotation rate of the flywheel rotor. This paper discusses one of the possible options for mathematical study of the stated problem, namely, application of structural analysis based on graph theory. Within the framework of the stated problem a graph was constructed for generating the new required rate, while in order to consider the stochastic case option the incidence and adjacency matrices were constructed. The stated problem was solved using a power matrix which transforms a set of contiguous matrices of the graph of admissible solution edge sequences, the real-time control function was found. Based on the results of this work, operational trials were run for the developed control function of the flywheel motor rotor rotation rate, a math model was constructed for the real-time control function, and conclusions were drawn about the feasibility of implementing the results of this study. Key words: Control function, graph, incidence matrix, adjacency matrix, power matrix, microcontroller control of the flywheel motor, highly dynamic spacecraft.


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