The Close Relationship between Internal Wave and Ocean Free Surface Wave

A numerical model was used to simulate the propagation of internal waves (IW) along the surface layer. The results show that strong water exchange during IW propagation results in strong free surface flow and produces small but distinct free surface waves. We found a close relationship between the internal and ocean surface waves. Our intuitive reaction is that by training the relationship between the water surface wave height and the internal wave waveform, the internal wave waveform can be reversed from the water surface wave height value. This paper intends to validate our intuition. The artificial neural network (ANN) method was used to train the Fluent simulated results, and then the trained ANN model was used to predict the inner waves below by the free surface wave signal. In addition, two linear internal wave equations (I and II) were derived, one based on the Archimedes principle and the other based on the long wave and Boussinesq approximation. The prediction by equation (II) was superior to the prediction of equation (I), which is independent of depth. The predicted IW of the proposed ANN method was in good agreement with the simulated results, and the predicted quality was much better than the two linear wave formulas. The proposed simple method can help researchers infer the magnitude of IW from the free surface wave signal. In the future, the spatial distribution of IW below the sea surface might be obtained by the proposed method without costly field investigation.

Modelling a suspension for an experiment to measure the speed of gravity in short distances

An experiment to measure the speed of gravitational signals in short distances has been developed with the intention to study its behavior when a medium different from air is allocated between the emitter and the detection and check if the speed of the interaction changes. The experiment is composed of three sapphire bars that vibrates, and as they vibrate its creates a tidal gravitational wave signal that interacts with another sapphire bar, this bar is monitored by a very pure microwave signal and its amplitude and phase are measured and the gravity speed is calculated, all system is cooled to a temperature of 4.2 K to increase sensitivity and kept in high vacuum. The sapphire bar needs to be suspended to avoid seismic noise and other interference. This work models the sapphire bar with the suspension, a wire that suspends the bar by its center and has its performance calculated in a finite element modelling. The final result shows that the mechanical behavior of the sapphire bar is not affected by the suspension.