Abstract: Method for monitoring a body inserted in pipe conducting a fluid flow, the body being positioned in a distance from the pipe wall providing a gap between the body and the pipe wall, the gap constituting an electromagnetic, e.g. microwave, resonator, at least one coupling probe being positioned close to said gap, the method comprising the steps of applying an electromagnetic signal, monitoring the frequency response of the resonator through the probe, and analyzing the frequency response to provide a measure of movements, e.g. vibrations induced by a turbulent flow, of the body. The invention also relates to an insert with support structure especially shaped to avoid influence on the resonance measurement.

Abstract: Method for monitoring a body inserted in pipe conducting a fluid flow, the body being positioned in a distance from the pipe wall providing a gap between the body and the pipe wall, the gap constituting an electromagnetic, e.g. microwave, resonator, at least one coupling probe being positioned close to said gap, the method comprising the steps of applying an electro-magnetic signal monitoring the frequency response of the resonator through the probe, and analysing the frequency response to provide a measure of movements, e.g. vibrations induced by a turbulent flow, of the body. The invention also relates to an insert with support structure especially shaped to avoid influence on the resonance measurement.