Pezhman Mardanpour

The human urge to achieve power from nature has shaped the evolution of wind turbines, enabling the conversion of wind into useful energy. This article unveils the evolutionary aeroelastic design of wind turbines from the perspective of Constructal Law, the physics of design that analyzes, explains, and predicts how energy flow configurations evolve to survive. Witnessing the evolution of wind turbines from early vertical axis to modern horizontal-axis configurations, the article highlights changes in tower height, rotor size, and material quantity that follow predictable patterns in design and performance, while identifying scaling relationships and structural constraints that influence efficiency. Key predictions include proportional relationships between rated power and tower mass, as well as among nacelle mass, rotor mass, and tower mass. The study demonstrates that several design shifts in history have consistently enhanced energy flow configurations, conceived as designs, and structural performance. These insights empower designers to fast-forward with confidence the evolution of wind turbine power systems.

Origami, the art of paper folding, has long fascinated researchers and designers in its potential to replicate and tap the complexity of nature. In this paper, we pursue the crossing of origami engineering structures and biology, the realm of biologically-inspired origami structures categorized by the two biggest taxonomy kingdoms and DNA origami. Given the diversity of life forms that Earth comprises, we pursue an analysis of biomimetic designs that resemble intricate patterns and functionalities occurring in nature. Our research begins by setting out a taxonomic framework for the classification of origami structures based on biologically important kingdoms. From each of these, we explore the engineering structures inspired by morphological features, behaviors, and ecological adaptations of organisms. We also discuss implications in realms such as sustainability, biomaterials development, and bioinspired robotics. Thus, by parlaying the principles found in nature’s design playbook through the art of folding, biologically inspired origami becomes fertile ground for interdisciplinary collaboration and creativity. Through this approach, we aim to inspire readers, researchers, and designers to embark on a journey of discovery in which the boundaries between art, science, and nature are blurred, providing a foundation for innovation to thrive.

Body-freedom flutter characteristics of flying wing aircraft vary with engine placement. Here, we show why a certain design parameter (engine placement) influences the aeroelastic flight envelope of the aircraft. The approach is based on the constructal law and the principle that a design that avoids stress strangulations provides better access to the flows that inhabit the system. This is in sharp contrast with trial-and-error techniques such as optimization, which means to opt from among different choices, cases, and designs. Under the same flight condition, the flow of stresses through the aircraft wings is investigated for several configurations including those with maximum and minimum flutter speeds. The results reveal that when the stresses flow smoothly in the wings the stability of the aircraft improves. On the other hand, in the cases in which the engine location causes stress strangulation, the flutter speed decreases considerably. The most severe stress strangulation corresponds to the aircraft configuration with minimum flutter speed (i.e., engine placement at 20% span behind the reference line). The smoothest flow of stresses happens in the configuration with maximum flutter speed (i.e., engine placement at 80% span forward of the reference line).

Nonlinear aeroelastic responses of a flying wing aircraft due to different gust profiles are investigated. Three different gust profiles are obtained considering light, moderate, and severe turbulence. A flying wing configuration is designed for the purpose of this investigation. The structural properties of the wings are obtained using VABS software, and then the flying wing is simulated with Nonlinear Aeroelastic Trim and Stability of HALE Aircraft (NATASHA) computer program. The results of time domain analysis are reported for the cases when engine is placed at the root of the wing and close to the area of maximum flutter speed. It has been found that the flying wing experiences limit cycle oscillation, when the engines are mounted at the root of the aircraft, for all three gust profiles. However, when the engines are placed at the area of maximum flutter speed, the oscillations die out. In addition, the real and imaginary part of eigenvalues and the unstable mode shape of the aircraft are reported.

The aeroelastic behavior of high-aspect-ratio very flexible flying wing is highly affected by the geometric nonlinearities of the aircraft structure. This paper reviews the findings on how these nonlinearities influence the structural and flight dynamics, and it shows that the aeroelastic flight envelope could significantly be extended with proper choices of design parameters such as engine placement. Moreover, in order to investigate the physics behind the effects of design parameters, constructal theory of design is reviewed. The constructal theory advances the philosophy of design as science, it states that the better structural design emerges when stress flow strangulation is avoided. Furthermore, it shows that airplanes, through their evolution, have obeyed theoretical allometric rules that unite their designs.