Measuring the Fluid Flow Velocity and Its Uncertainty Using Monte Carlo Method and Ultrasonic Technique AHMAD S. AWAD 1 , ZAID ABULGHANAM 1 , SAYEL M. FAYYAD 1 , SAMEH ALSAQOOR 2 , ALI ALAHMER 2,3 , NADER ALJABARIN 4 , PIOTR PIECHOTA 5 , ARTUR ANDRUSZKIEWICZ 5 , WIESŁAW WĘDRYCHOWICZ 5 AND PIOTR SYNOWIEC 5 1 Mechanical Engineering Department, Faculty of Engineering Technology, Al-Balqa` Applied University, Amman-Jordan, (corresponding author, Email: ahmad.awwad@bau.edu.jo). 2 Department of Mechanical Engineering, Faculty of Engineering, Tafila Technical University, P.O. Box 179, Tafila 66110, JORDAN 3 Department of Alternative Energy Technology, Faculty of Engineering and Technology, Al- Zaytoonah University, P.O. Box 130, Amman 11733, JORDAN 4 Department of Natural Resources and Chemical Engineering, Faculty of Engineering, Tafila Technical University, P.O. Box 179, Tafila 66110, JORDAN, 5 Wrocław University of Science and Technology, Wybrzeże Stanisława Wyspiańskiego 27, 50-370 Wrocław, POLAND Abstract: One of the most important challenges in fluid mechanics, gas dynamics, and hydraulic machinery fields is measuring the flow velocity with high accuracy. It is more important in large systems; such as thermal power stations, large scale power generations, and combined cycle power plants. The exact estimation of the measurement uncertainty inflow velocity is extremely importantin evaluating the accuracy of the measurement. This work describes the problem of estimating measurement uncertainty when there are two or more dominant components of the uncertainty budget.Two methods, analytical and numerical methods are used to study the comparative analysis for the results of determining the expanded uncertainty of measurement using two methods: analytical method and the numerical method. The analytical method uses the law of uncertainty propagation and is based on the estimation of uncertainty values of type A and B, while the numerical technique depends on the evaluation of measured samples by the Monte Carlo method using a random number generator. The aim of this article is to show the Monte Carlo method as an alternative way to determine the distribution of individual components of the measurement uncertainty budget. Also, the measurement of liquid flow velocity by an ultrasonic method has been analyzed, which is commonly used due to high measurement accuracy and non-invasiveness. Due to the complexity of the equation defining the measured flow velocity, determining the measurement uncertainty is not an easy task. Keywords: Measurement Uncertainty, Monte Carlo Method, Flow Measurement, Ultrasonic Flow Meter. Received: June 1, 2020. Revised: October 13, 2020. Accepted: October 21, 2020. Published October 31, 2020 WSEAS TRANSACTIONS on FLUID MECHANICS DOI: 10.37394/232013.2020.15.17 Ahmad S. Awad et al. E-ISSN: 2224-347X 172 Volume 15, 2020