Ehsan Ardekani, Mohammad Ali Ardekani, Foad Farhani,
Volume 25, Issue 1 (12-2024)
Abstract
One of the methods to improve the performance of the vortex flowmeter, especially for low flowrate, is to use a dual bluff model that increases the vortex shedding frequency. In this experimental research work, the vortex shedding from a dual cylindrical bluff model of semicircular cross-section, at different l d ratios, where d is the diameter and l is the distance between the two semicircular cylinders in series is measured and investigated using a wind tunnel and hot-wire anemometer. Results show that the Strouhal number for dual bluff body depends on the Reynolds number and l d . In the range of 0/8≤ l d <2 , the Strouhal number has changes and jumps compared to the Reynolds number. Therefore, it is not suitable for vortex flowmeter application. also show that the velocity frequency spectrum, it can be determined that the highest value of the turbulent intensity is related to the oscillating velocity with the vortex shedding frequency, and therefore, to investigate the strength of vortex shedding frequency, the turbulent intensity was investigated, that the value of turbulent intensity depends on Reynolds number and l d . Considering the standard deviation of the repeatability of the Strouhal number reading and also the strength of the vortex shedding frequency (investigation of the turbulent intensity), for 0< l d <0/8 and 2≤ l d ≤3 , a dual cylindrical bluff model of semicircular cross-section, placed in series, is suitable for vortex flowmeter application
