Nonlinear dark envelope wave in fluid-filled elastic tubes

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This paper investigates nonlinear wave propagation in fluid-filled elastic tubes relevant to arterial pulse dynamics. Using the KdV equation, we derived the nonlinear Schrödinger equation (NLSE) from the coupled fluid structure equations, and analytical dark envelope soliton solutions are obtained. Numerical simulations based on a fourth-order Pad compact finite-difference scheme and Runge–Kutta method show excellent agreement with the analytical results, confirming the stability and accuracy of the model. The study reveals that wave propagation characteristics strongly depend on the mechanical properties of the elastic tube, providing a theoretical basis for understanding pulse wave dynamics and potential applications in cardiovascular diagnostics.