Ridge localization driven by wrinkle packets

Area of Science:

• Fluid dynamics
• Materials science
• Instability analysis

Background:

• Buckling of films on elastic substrates is time-independent.
• Time evolution is crucial for buckling on viscous fluid substrates.
• Understanding fluid-structure interactions is key in materials science.

Purpose of the Study:

• To analyze time-dependent buckling instabilities in fluid-structure interactions.
• To model the emergence of imperfections from initial noise.
• To investigate the transformation of wave packets into localized structures.

Main Methods:

• Analysis of a growth function that amplifies initial noise.
• Convolution of the growth function with experimental or numerical noise.
• Experimental observation of wave packet amplification and dilution.

Main Results:

• Buckling instabilities in fluid-structure interactions are governed by a growth function.
• Initial noise is amplified, leading to wave packets with large-scale modulation.
• Wave packets transform into ridges at low compression rates and wrinkles at high compression rates.

Conclusions:

• The study provides a framework for understanding time-dependent buckling in fluid-structure systems.
• Natural imperfections emerge from the interplay of growth functions and noise.
• Compression rate dictates the final morphology, transitioning from ridges to wrinkles.