A data acquisition programme was performed within the "Submarine Vortex Shedding" (S.V .S.) research project to check the response of a full scale free spanning pipeline in real environment subject to the action of predominant wave flow (first site) and predominant steady current (second site).

The sites chosen were the Adriatic Sea, offshore the coast of Ravenna for the first case and the northern entrance of the Lagoon of Venice, called Porto Lido Channel, for the second one.

Full scale models were arranged and instrumented in each site, and thorough environmental monitoring systems were employed.

Numerous data was gathered, covering the periods ranging from February to May 1987 in the offshore of Ravenna and from August to October 1987 in the Lagoon of Venice.

Model set-ups, instrumentation, organization and the results from the analyses of data are described.


The purpose of the S.V.S. research project is to deepen the knowledge of the hydroe1astic phenomena affecting sea1ines, induced by the shedding of vortices in the different flow conditions existing in nature such as steady flow, oscillatory flow and a combination of both several research projects were carried out in the past with the same aim. Generally these works were based on laboratory tests and considered ideal situations. Among all we would like to recall the work performed by Sarpkaya, Tsahalis, Jacobsen and others, Sumer and others.

On the other hand, data resulting from in field surveys are not so many.

We quote Wooton and others, who studied the hydroelastic oscillations affecting piles of various diameters and stated the bases of the Rules applied at present. Bruschi and others studied the behavior of a full scale span in steady flow, operating in the Lagoon of Venice.

Raven and others dealt with a full scale span subject to a uniform stream, as part of a wider research project.

The S.V.S. Project included an ample program of in-field activities, regarding two sites affected respectively by wave dominated sea states and predominant steady current.

In both cases, an experimental set-up was designed and installed with the purpose of collecting data to describe the studied phenomena. As regards wavy flows, the site chosen was an area offshore Marina di Ravenna; the site presented a high probability of obtaining wave motion values suitable to enhance hydroelastic oscillations on a purposely designed full scale model.

The operations were performed near the AGIP PCWA platform, used as support base, where the depth was approx. 12 m and the wave motion remarkable. Construction, instrumentation of the set-ups and data acquisition took place from February to May 1987.

As regards predominantly steady current, an area was identified inside the Porto Lido Channel, the northern inlet of the Lagoon of Venice. Here strong tidal streams, quite unique in Italy, are present in a well predictable succession, that does not hinder field operations.

In this area the seafloor is sandy and even. Here operations lasted from May to October 1987.

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