“…Consequently, it is recommended to conduct research that allows for the investigation of the influence of obstructions (knees, gate valves, constrictions, and throttles) on ultrasonic flow-meter readings. Previous studies [15][16][17] have addressed the issue of ultrasonic flow measurement under non-standard measurement settings downstream of a pipeline elbow. This study focused on the data acquired downstream of a butterfly valve with a manual closing angle.…”