PA - Simulation study of a Piezoelectric-Based Whisker Sensor Array

Simulation study of a Piezoelectric-Based Whisker Sensor Array for underwater Point source vibration measurements

Abstract:

When a fish moves in water and flicks its tail, it can create a von Kármán vortex street (VkVS). This phenomenon occurs due to the separation of water flow from the fish’s tail, resulting in the formation of vortices behind the tail that alternately emerge from both sides. These vortices form in a regular and periodic manner behind the fish, creating a vortex street. This process helps the fish move more efficiently through water and reduces the drag force against its movement. Seal whiskers are highly sensitive and are specifically adapted to detect minute vibrations and movements in the water. This ability is critical for hunting and navigation, especially in murky or dark waters where visual cues are limited. Seals can detect the mentioned vortex-like vibrations, which can linger in the water for several minutes, using their whiskers. The capability of seals to hunt fish is based not only on the sensitivity but also on the design of the structure of their whisker array. The aim of this project is to simulate the 2D time-domain von Kármán vortex street phenomena for different amplitudes of movement (single and two-point vortex) and simulate the signal behavior of the whisker sensor array under different conditions. This data will then be integrated into the next model for evaluating the whisker sensor array (3×2) which is designed based on the piezoelectric measurement principle. A parametric study will be investigated for the sensor configuration, whisker elasticity, and length to explore a relation between vortex vibration amplitude, detection distance range, and sensory features needed. The project outcome is expected to provide a comprehensive understanding of the whisker array sensor behavior and create a dataset for engineering requirements such as sensitivity for the fabrication phase.

Tasks and Duties:

o   Conduct a review of existing research in this field.

o   Model the VkVS effect with one or two sources.

·        Start with a stationary model and expand it in the time domain.

·        Perform a parametric study to understand the relationship between vortex and distance/amplitude.

o   Model the piezoelectric whisker sensor.

·        Begin with a single sensor and expand it into an array shape.

·        Use the dataset of vibration from the previous step and plot the sensor signal.

·        Design the whisker sensor to cover a range of frequency bands based on the parametric study of material, length, and elasticity.

o   Ideally, generate a 3D integrated model.

·        With the experience and knowledge gained from the previous phases, build a sensor array in a water environment with two vibration sources.

o   Signal processing.

·        Perform FFT to detect and prove the signal vibration frequency.

·        Investigate the potential features that can be extracted from the sensor array signals, such as the width of the object or distance.

 Requirements:

·       Good knowledge in vibration analysis and laminar flow dynamics

·       Basic understanding of piezoelectric materials.

·       Strong motivation for learning simulation software (COMSOL).

·       Interest in learning basic signal processing.

·       Strong analytical and problem-solving skills.

Contact Person: Mohammad Sadeghi (mohammad.sadeghi@tuhh.de)

Desired starting date: As Soon As possible