## 2 Methodology
### Experimental Details
* Current and voltage sensors: to measure the electrical power created by the hydrokinetic turbine, current sensors (ACS712, SparkFun Electronics, Boulder, CO, USA) and voltage sensors (DC0-25V, MAKERS Electronics, Alexandria, Egypt) were installed. These sensors allowed us to screen the electrical current moving through the system and the voltage across the PMDC motor, which are fundamental for computing the generated power. The accuracy of the ACS712 current sensor was within \(\pm\)1.5% and the accuracy of the DC0-25V Voltage Sensor was within \(\pm\)0.5%. * Temperature and humidity sensors: For safety and performance monitoring, temperature and humidity sensors were installed. Two sensors of type SHT30 (Sensirion, Stafa, Switzerland) and two of type DHT22 (Kuongshun Electronic, Shenzhen, China) were utilized to measure the temperature and humidity levels inside the turbine nacelle. The accuracy of the SHT30 temperature and humidity sensor was within \(\pm\)2% for humidity and \(\pm\)0.3 \({}^{\circ}\)C for temperature, and the accuracy of the DHT22 temperature and humidity sensor was within \(\pm\)2% for humidity and \(\pm\)0.5 \({}^{\circ}\)C for temperature. Table 2 provides a clear overview of the sensors used, their accuracy, and their respective purposes in the experimental setup. The insert setup, which includes all these sensors and equipment, is shown in Figure 3.  
To process and analyze these data, a data acquisition system was employed. In this case, a National Instruments (NI) SCXI-1000 data acquisition system (Austin, TX, USA), integrated with LabVIEW software (v.8.5.1), was used. This system is capable of gathering analog signals from various sensors. The data collected by these sensors are indispensable for understanding the presentation and conduct of the hydrokinetic turbine model during testing. By estimating force, rotational speed, electrical current, voltage, temperature, and humidity, we can obtain comprehensive information on the turbine's proficiency, power generation capabilities, and safety boundaries. The testing procedure for understanding the hydrodynamic characteristics of the hydrokinetic turbine consists of several meticulously planned steps, ensuring accurate and reliable data collection. * Positioning the Hydrokinetic Turbine Model Before conducting the experiments, the hydrokinetic turbine model is carefully positioned in the towing tank. This initial step is critical as it sets the foundation for all subsequent measurements and observations. The turbine model is situated appropriately relative to the towing arm, ensuring that it remains stable and aligned throughout the testing process. The insert part containing the electro-machine and sensors is securely connected to the torpedo nacelle, ensuring a watertight seal. This assembly is crucial for preventing water ingress, which could potentially damage sensitive electronic components and compromise data integrity. The precision in positioning the turbine model guarantees that the experimental setup accurately reflects real-world conditions, thereby enhancing the validity of the results. * Submerging and Towing the Turbine Model Once the turbine model is securely placed in the towing tank, it is submerged and prepared for the towing process. The model is towed through the water at a pre-selected speed, which can be adjusted based on the specific requirements of the test. This controlled towing process simulates various flow conditions that the turbine would encounter in an actual operational environment. During this phase, sensors