Abstract: Techniques for measuring a density of a liquid within a fluid that includes both a liquid and a gas are described. A pressure of the fluid oscillates according to a time-varying function, which causes a density of the fluid also to oscillate according to the same time-varying function. A resulting pressure signal and density signal are analyzed to extract at least a first and second pressure value and at least a first and second density value, where the first pressure and density values occur at a first time, and the second pressure and density values occur at a second time. Then, the liquid density is calculated from the first and second pressure and density values. As a result, the liquid density may be calculated quickly and easily, with a minimum of effort on the part of an operator, and without requiring disruption of other measurement processes associated with the flowtube.

Abstract: A flowmeter is disclosed. The flowmeter includes a vibratable flowtube, and a driver connected to the flowtube that is operable to impart motion to the flowtube. A sensor is connected to the flowtube and is operable to sense the motion of the flowtube and generate a sensor signal. A controller is connected to receive the sensor signal. The controller is operable to determine a first flow rate of a first phase within a two-phase flow through the flowtube and determine a second flow rate of a second phase within the two-phase flow.

Abstract: A method for determining the pulsatile flow characteristics in fluid flow driven by a periodic pressure disturbance includes the step of evaluating the spectrum of a signal representative of the vortices generated by a vortex flowmeter. Because of the periodic pressure disturbance, the signal is an FM signal in which a carrier, having a frequency corresponding to the vortex-shedding frequency in the absence of pulsating flow, is modulated by the periodic pressure disturbance. The pulsation frequency and amplitude are then estimated on the basis of the separation between adjacent sidebands of the spectrum of the FM signal and the relative amplitudes of the sidebands.