Transition to chaotic flow, bifurcation, and entropy generation analysis inside a stratified trapezoidal enclosure for varying aspect ratio

•Identified critical Grashof numbers for symmetric, periodic, and chaotic flow transitions.•Analyzed heat transfer and entropy generation in trapezoidal enclosures with varying ARs.•Found HT irreversibility dominant at low Gr and FF irreversibility at high Gr.•Demonstrated ECOP decreases with increasing aspect ratios, indicating reduced entropy.•Provided insights into optimizing thermal management systems in engineering applications.