Estimation by Inverse Approach of a Transmissivity Field over the Entire Continental Terminal Aquifer of Abidjan

Hydraulic characterization of aquifer systems is important for the development of exploitation scenarios and groundwater management strategies. Especially in lithologically heterogeneous aquifers, local scale variations in transmissivity (T) may not be neglected. Field scale transmissivity values are usually derived from pumping tests, but in most cases their number and availability are rather limited. Thus, direct measurement of transmissivity over an entire aquifer is expensive and technically almost impossible. In such situations, inverse hydrodynamic modelling is the appropriate solution. In this article, the real transmissivity field of the aquifer of the Continental Terminal of Abidjan is investigated by a multi-scale parametrization that allows to bypass the problem of scale change and to determine this hydrodynamic parameter over the entire aquifer. This hydrogeological modelling of the Continental Terminal aquifer identified a structure of 153 nodes in size as the closest structure to that of the Continental Terminal aquifer. The transmissivity field associated with this optimal size, ranging from 5.4.10-5 to 1 m2s-1, has been compared with values published in other studies in Africa and the world. These identified values are plausible and have a good overall structure. The success of this modeling is strongly linked to the quantity, quality and spatial distribution of authentic informations on the parameters sought.

The Effect of Sensor Structure and Coplanar Electrode for Capacitive Based Flow Sensor

This paper presents the analysis of the capacitive based flow sensor using computational fluid dynamic (CFD) and mathematical equation approach. The CFD simulations for different types of sensor structure were carried out. Pressure and velocity of the fluid were varied in order to study the hydrodynamic parameter such as displacement and drag force. For the coplanar electrode, width of electrode and half gap between electrodes were varied for capacitive response using mathematical approach. Based on the simulation, the displacement of the dome increases as the pressure increases. The result shows that the most suitable thickness of the dome is 0.1 mm based on the displacement and the strain. Meanwhile for the coplanar electrode, the width and half gap showed a significant effect on the capacitance response.

A Feasibility Study of Applying Laser Line Scanning to AUV Hydrodynamic Parameter Identification

Precise control is a key factor in enabling Unmanned Underwater Vehicles (UUVs) to complete various underwater activities. The development of UUV control rules is mostly based on UUV dynamic models. However, such dynamic models contain unknown hydrodynamic parameters that need to be identified. This paper presents a new method, Laser Line Scanning for Hydrodynamic Parameter Identification (LSHPI), which integrates laser line scanning, decoupled dynamics, and evolutionary optimisation to identify the hydrodynamic parameters of an Autonomous Underwater Vehicle (AUV). In this research, laser images, seen from an on board camera's perspective and created using Open Graphics Library (OpenGL), were used to validate LSHPI's feasibility. The accuracy of the AUV positions and Euler angles obtained by the laser image-based methods were investigated for each decoupled One-Dimensional (1D) motion and the influence of other motion disturbances on the accuracy of the obtained AUV positions or Euler angles was also evaluated. In addition, the accuracy of the surge-related hydrodynamic parameters obtained by LSHPI was investigated under different motion disturbances. Based on the hydrodynamic parameter identification results under different motion disturbances, LSHPI's feasibility was successfully validated.