The radiation by a submerged fluid-filled cylindrical shell in response to a transient external pressure pulse is considered, and a semi-analytical model based on the Reissner–Mindlin shell theory is employed to simulate the interaction numerically. Two types of radiated waves that have been previously seen in experimental images for a submerged evacuated cylindrical shell are observed in both the external and internal fluids, the symmetric Lamb waves S0 and the antisymmetric Lamb (or pseudo-Rayleigh) waves A0. The third type of radiated waves is also observed that has not been explicitly imaged either experimentally or numerically for a submerged evacuated cylindrical shell, and it is demonstrated that these waves are the Scholte–Stoneley waves A. The effect that the complex structure of the radiated field has on the wave phenomena in the internal fluid is analyzed for shells of several different thicknesses, and the results of this analysis are summarized in the form of diagrams suitable for the use at the pre-design stage.

We present a semi-analytical approach, based on the Reissner-Mindlin shell theory, for the numerical analysis of the interaction between elastic circular cylindrical shell structures and external acoustic pulses or weak shock waves. We discuss the advantages and limitations of the approach over alternative methodologies and provide numerical results for the case of a submerged fluid-filled shell.

We consider a submerged fluid-filled cylindrical shell subjected to an external acoustic pulse and analyze the structure of the field radiated by the shell into the fluids, both external and internal. We first propose a computationally efficient semi-analytical model of the interaction based on the Reissner-Mindlin shell theory combining some of the classical methods of mathematical physics with the finite-difference methodology, and then use the model to simulate the interaction. We demonstrate that the model accurately reproduces the wave structure of the radiated fields seen in the experiments for submerged evacuated shells, namely, both the symmetric Lamb waves S0 and the pseudo-Rayleigh waves A0. It is further observed that the internal and external wave patterns associated with the A0 waves exhibit the same alternation of the equiphase lines as the one seen in the experiments for a plate loaded by the fluid on both sides, a result that seems to be particularly relevant in the context of very limited number of experimental images of the radiated field for shells loaded by fluid from both inside and outside. Not less interestingly, we also demonstrate that the Scholte-Stoneley, or A, wave is also reproduced by the model, and we offer some insights into the non-observability of this wave for certain types of cylindrical shells reported in earlier experimental studies.

We introduce a robust and computationally efficient methodology for numerical simulation of shock-structure interaction. The methodology is based on the use of some of the classical methods of mathematical physics, with the subsequent coupling between the fluid dynamics and structural parts using the finite-difference methodology. In order to demonstrate the versatility of the approach, we apply it to two rather different practically important problems of the interaction between shock waves and submerged cylindrical structures, aiming at providing insights that would be useful to engineers at the pre-design stage.We first consider a submerged cylindrical shell subjected to two consecutive shock waves, and analyze the effect of such loading in the context of both hydrodynamic fields and the structural stresses it induces. The most important result of this analysis is the observation, for certain values of the distance between the wavefronts, of a very significant increase of the maximum stress observed in the structure.Then, we consider a submerged cylindrical shell subjected to a single shock wave, but employ a more advanced shell theory than the one traditionally used, namely, the Reissner-Mindlin theory instead of the Kirchhoff-Love one. We demonstrate that such an advancement of the model not only leads to a very significant improvement of the accuracy of the respective simulations, but also allows for modeling relatively thick shells.

Accurate modeling of the structure of the acoustic field radiated by a submerged cylinderical shell responding to an external pulse is presented. A thin evacuated elastic circular cylindrical shell submerged into fluid is considered and it is modeled using the Reissner-Mindlin theory of shells. A steel shell is considered with the thickness of 0.03 m and the radius of 1 m, submerged into water. The fluids and the shell are coupled through the dynamic boundary condition on the interface. The results show that simulations of the stress state of the shell based on RM model take only 13% longer than those based on the KL model. Simulated time-histories of the acoustic pressure were evaluated at several points of the fluid to the available experimental time-histories for similar systems, and a very good match for the the waves is observed.

We consider a number of non-stationary fluid-structure interaction problems that represent several different scenarios of impulse acoustic loading on a fluid-contacting elastic circular cylindrical shell. Both the submerged evacuated and submerged fluid-filled shells are addressed, along with shell systems of higher structural complexity. We discuss the semi-analytical approach that was developed to model such systems, and highlight its advantages and limitations. In particular, we discuss the recent enhancement of the approach that allowed for a much more accurate modeling of the fine structure of the radiated field including the adequate reproduction of all types of the structure-induced waves seen in the experiments. We also address a number of interesting and practically important acoustic effects that we observed in the systems in question. In particular, we discuss the effect of the acoustic phenomena in the internal fluid volume on the structure of the external acoustic field, and analyze the propagation of the waves induced by additional structural elements incorporated into the system.

We consider a submerged evacuated circular cylindrical shell subjected to an external impulse loading and focus on the numerical simulation of the radiation by such a shell into the surrounding fluid. The structure of the radiated field in question is complex, and the only fully successful attempts at its numerical simulation were those where the shell was treated as an elastic body, i.e. where all the assumptions accommodating the distinctive geometry of a shell were abandoned. Our objective is to attempt introducing a mathematical model of the system that would be based on a shell theory more advanced than the ones used so far in the present context but that, at the same time, would produce the results of the same level of accuracy as the more complex, non-shell-theory-based models. We demonstrate that this is indeed possible, and that employing the Reissner–Mindlin shell theory within the framework of the semi-analytical methodology developed in our earlier work allows for an accurate reproduction of the structure of the radiated field without resorting to treating the shell as an elastic body.

An elastic shell filled with and submerged into different fluids is subjected to an external acoustic pulse. It is found that the diversity of the internal reflection and focusing phenomena is such that it leads, for certain combination of the parameters of the fluids, to a very considerable increase of the pressure in the fluid which in some cases can be as high as 110% of the peak incident pressure. A thin elastic circular cylindrical shell filled with and submerged into different fluids is considered. The fluids are assumed to be irrotational, inviscid, and linearly compressible, thus the wave equations are used to model the fluid dynamics. The results show that the tensile stress is affected by the changes of the acoustic properties of the fluids, so much so that it prompts a separate discussion of the matter.

A study that was conducted examine the extreme acoustic pressure in multi-fluid shell systems subjected to an external pulse is presented. A thin elastic circular cylindrical shell was considered, which was filled with and submerged into different fluids. It was assumed that the shell is thin enough, and that its deflections are small in comparison to its thickness, so that the linear shell theory can be employed. It was further assumed that the LoveKirchhoff hypothesis holds true. The pressure is then obtained as a Fourier series with time dependant coefficients which, for the radiation pressure depend on the unknown normal displacements of the shell. Then, the same series form is used for the shell displacements and, substituting them into the shell equations, researchers arrive at the systems of the ordinary differential equations for each of the displacement harmonics.

A study that was conducted to examine acoustic response of multi-fluid shell systems with structural Enhancement is presented. A thin elastic circular cylindrical shell was considered of a given radius, which was filled with and submerged into different fluids. It was assumed that the shell is thin, and that its deflections are small in comparison to its thickness, so that the linear theory of shells can be employed. A steel shell is considered with the thickness of 0.01 m and radius of 1 m, submerged into and filled with fluids of the same density but with varying acoustic speeds. Furthermore, the entire sequence of the internal pressure wave propagation, reflection, and focusing was shifted in time which results in the head waves seen in front of the incident wavefront.

Several most important features of the hydrodynamic field induced inside a circular cylindrical shell filled with and submerged into different fluids when it is subjected to an external shock wave are considered. This investigation is a follow-up of an earlier study of the two-fluid shell-shock interaction [S. Iakovlev, Interaction between an external shock wave and a cylindrical shell filled with and submerged into different fluids, Journal of Sound and Vibration 322 (2009) 401–437], and it addresses a number of practically important issues not covered in that work. The focus of this study is on the evolution of the respective hydrodynamic patterns in response to the continuous change of the parameters of the fluids, in particular the speed of sound. Along with the analysis of the hydrodynamic patterns it is also demonstrated that when one is concerned with the highest pressure attained inside the shell, the most dangerous combination of the parameters occurs when the ratio of the internal and external acoustic speeds is close to 0.48, with the respective pressure exceeding the maximum incident pressure by more than 110 percent. The effect that the hydrodynamic features discussed have on the stress state of the shell is addressed as well, and it is observed that the maximum tensile stress is significantly affected by the evolution of the considered hydrodynamic features, whereas the maximum compressive stress is not. It is also observed that the maximum tensile stress is very sensitive to the change of the ratio of the acoustic speeds in the internal and external fluids, with as little an increase of the latter as 13 percent resulting in more than doubling of the former in some cases.

The analysis of the hydrodynamic fields induced in cylindrical shells by an external shock loading is presented. The model of irrotational, inviscid, and linearly compressible fluid is used, and the shell is assumed to be thin enough for the linear theory of shells to apply. The fluids and the shell are coupled through the dynamic boundary condition on the interface. The finite difference technique was employed to obtain the harmonics of the shell displacements. The simulated images based on the solution developed were compared to the available experimental ones for some of the pressure components. It was observed that the dynamics of the acoustic field when the fluids are identical.