About

Dr. Haibo Dong is the founder of the Dong Research Group, established in 2006 and located in the Mechanical and Aerospace Engineering building at the University of Virginia. His research group focuses on understanding the physics of complex flows related to flying and swimming in nature. This is achieved by integrating state-of-the-art computational methods, experimental tools, and theoretical fluid dynamics research. The group's research is motivated by fundamental fluid dynamics questions as well as practical applications. The Dong Research Group is equipped with advanced technology including a high-speed photogrammetry system with three synchronized and calibrated high-speed cameras, IBM NeXtScale computer clusters with 200 cores and 1TB of RAM, and a file server with 150 TB of disk capacity designed for high-fidelity flow solvers. Their tools also include flow visualization and analysis systems developed to study unsteady vortex-dominated flow problems. Current research areas in Dr. Dong's group include biological fluid dynamics, insect flight, fish swimming, fluid-structure interaction, reduced order modeling, Cartesian grid methods, high-performance computing, high-speed photogrammetry, and biomedical applications such as phonation and sleep apnea.

Research topics

• Physics
• Mechanics
• Classical mechanics
• Computer Science
• Engineering
• Fishery
• Aerospace engineering
• Thermodynamics
• Anatomy
• Optics
• Geology
• Simulation
• Marine engineering
• Biology

Selected publications

• Hydrodynamic interactions of low-aspect-ratio oscillating panels in a tip-to-tip formation

  Journal of Fluid Mechanics · 2026-03-02

  articleOpen accessCorresponding

  The vertical, tip-to-tip arrangement of neighbouring caudal fins, common in densely packed fish schools, has received much less attention than staggered or side-by-side pairings. We explore this configuration using a canonical system of two trapezoidal panels (aspect ratio ${\textit{AR}}=1.2$ ) that pitch about their leading edges while heaving harmonically at a Strouhal number $St=0.45$ and a reduced frequency $k=2.09$ . Direct numerical simulations based on an immersed-boundary method are conducted over a Reynolds-number range of $600\leq {\textit{Re}}\leq 1\times 10^{4}$ , and complementary water-channel experiments extend this range to $1\times 10^{4} \leq {\textit{Re}}\leq 3\times 10^{4}$ . Results indicate that when the panels oscillate in phase at a non-dimensional vertical spacing $H/c\leq 1.0$ with $c$ denoting the panel chord length, the cycle-averaged thrust of each panel rises by up to 14.5 % relative to an isolated panel; the enhancement decreases monotonically as the spacing increases. Anti-phase motion instead lowers the power consumption by up to 6 %, with only a modest thrust penalty, providing an alternative interaction regime. Flow visualisation shows that in-phase kinematics accelerate the stream between the panels, intensifying the adjacent leading-edge vortices. Downstream, the initially separate vortex rings merge into a single, larger ring that is strongly compressed in the spanwise direction; this wake compression correlates with the measured thrust gain. The interaction mechanism and its quantitative benefits persist throughout the entire numerical and experimental Reynolds-number sweep, indicating weak ${\textit{Re}}$ -sensitivity within $600\leq {\textit{Re}}\leq 3\times 10^{4}$ , and across multi-panel systems. These results provide the first three-dimensional characterisation of tip-to-tip flapping-panel interactions, establish scaling trends with spacing and phase, and offer a reference data set for reduced-order models of vertically stacked propulsors.

  PublisherOA PDFDOI

• Design of A Lightweight Robotic Tensegrity Morphing Airfoil

  2026-01-08

  article

  This paper explores the design and fabrication of a robotic airfoil based on a tensegrity morphing structure. We begin by introducing a family of tensegrity morphing airfoil designs that convert a continuous airfoil shape into a discrete configuration. The airfoil structure is divided into two main components: a rigid section (the D-section head) and a flexible section (the tensegrity morphing tail). We compute aerodynamic forces using the panel method and, based on the drag and lift analyses, propose a morphing airfoil design and develop its CAD model. This model integrates all essential electronics, including the battery, PCB board, and motors, within the rigid D-section. The flexible tail is actuated by strings, enabling adaptive morphing. Our approach integrates lightweight tensegrity principles with adaptive design to create efficient morphing airfoil structures. The methodology is also applicable to bio-inspired wings, robotic fingers, grippers, and other soft robotic systems.

  PublisherDOI

• Fins in formation: hydrodynamic impact of median fins in in-line fish swimming

  Bioinspiration & Biomimetics · 2026-01-09

  articleOpen accessSenior author

  Abstract Median fins, including the dorsal and anal fins, influence fish propulsion by lowering body drag and increasing caudal fin thrust through active movement. While their role in solitary swimming is established, their impact on hydrodynamics within schooling environments remains unclear. Using high-fidelity computational fluid dynamics simulations of in-line fish pairs, we systematically varied median fin presence on leaders and followers to isolate neighbor-induced performance changes. When comparing the full-finned configuration to the finless configuration at a leader-follower streamwise spacing ( S ) of 1.1 body lengths ( l ), the follower’s drag was reduced by 9.5%. A significant contribution of the total drag reduction, about 70%, was neighbor-induced, arising from wake-body interactions with the wake of a leader that had median fins, while the rest was attributed to adding the follower’s own median fins. This neighbor-induced benefit arises from stronger leader-generated vortex structures that interact with the follower’s body, lowering both shear and pressure drag. The neighbor-induced benefits persist across a range of spacings, diminishing only beyond S = 1.4 l. At higher Reynolds numbers, the neighbor-induced drag reduction also dominates the total drag reduction of the follower. These findings reveal that median fins can serve as hydrodynamic tools for enhancing group swimming performance through neighbor-induced effects, extending their recognized functional role beyond self-induced improvements in solitary swimming.

  PublisherDOI

• Withdrawn: Design of a Lightweight Robotic Tensegrity Morphing Airfoil

  2025-01-03

  article
  PublisherDOI

• Numerical Analysis of the Aerodynamic Interactions in Tandem Flying Snake Airfoils

  Biomimetics · 2025-03-12 · 1 citations

  articleOpen accessSenior authorCorresponding

  During gliding, flying snakes flatten their ribs to create an airfoil-like cross-section and adopt S-shape postures, allowing upstream body segments to generate wake structures that affect the aerodynamic performance of downstream segments. This study investigates these interactions using numerical simulations of two-dimensional snake cross-sectional airfoils. By employing an immersed-boundary-method-based incompressible flow solver with tree topological local mesh refinement, various foil positions and movements were analyzed. The results show that aligning the downstream foil with the upstream foil reduces lift production by 86.5% and drag by 96.3%, leading to a 3.77-fold increase in the lift-to-drag ratio compared to a single airfoil. This improvement is attributed to the vortex-wedge interaction between the upstream vortex and the following foil's leading edge (wedge), which enhances the gliding efficiency of the posterior body. Furthermore, integrating specific pitching motions with coordinated vortex shedding could further optimize its lift production. These findings provide valuable insights into the aerodynamics of tandem flying snake airfoils, offering guidance for configuring optimal body postures for improving gliding efficiency.

  PublisherOA PDFDOI

• Tuna-Like Swimmers Experience a Fluid-Mediated Stable Side-by-Side Formation

  arXiv (Cornell University) · 2025-12-19

  preprintOpen access

  New free-swimming experiments and simulations are conducted on a pair of three-dimensional, bio-robotic swimmers composed of a body and tail section based on Yellowfin tuna, Thunnus albacares. It is discovered that the pair converges spontaneously to a side-by-side schooling formation that is stable to perturbations in the swimming direction at a fixed lateral spacing. We reveal that for close lateral spacings of 43% of the body length and thick, tuna-like bodies with a 22% thickness-to-length ratio, the flow between the swimmers is accelerated in a "channeling effect" due to flow constriction. Consequently, this creates a low-pressure zone that is the primary mechanism generating a fluid-mediated restorative force, thereby making the side-by-side formation hydrodynamically stable. This quasi-steady mechanism makes the stability of the formation insensitive to the phase synchronization between the bio-robots in contrast to previous results for schooling foils. Moreover, in the side-by-side formation tunalike swimmers are seen to have only a small reduction in their swimming speed and a concurrent small rise in their cost of transport. By leveraging this channeling effect, bio-robotic schools may be able to maintain a schooling formation with little or no control. This flow mechanism may also be present in biological schools of tuna-like fish where it may sculpt the formations observed in nature.

  PublisherDOI

• Tuna-Like Swimmers Experience a Fluid-Mediated Stable Side-by-Side Formation

  ArXiv.org · 2025-12-19

  articleOpen access

  New free-swimming experiments and simulations are conducted on a pair of three-dimensional, bio-robotic swimmers composed of a body and tail section based on Yellowfin tuna, Thunnus albacares. It is discovered that the pair converges spontaneously to a side-by-side schooling formation that is stable to perturbations in the swimming direction at a fixed lateral spacing. We reveal that for close lateral spacings of 43% of the body length and thick, tuna-like bodies with a 22% thickness-to-length ratio, the flow between the swimmers is accelerated in a "channeling effect" due to flow constriction. Consequently, this creates a low-pressure zone that is the primary mechanism generating a fluid-mediated restorative force, thereby making the side-by-side formation hydrodynamically stable. This quasi-steady mechanism makes the stability of the formation insensitive to the phase synchronization between the bio-robots in contrast to previous results for schooling foils. Moreover, in the side-by-side formation tunalike swimmers are seen to have only a small reduction in their swimming speed and a concurrent small rise in their cost of transport. By leveraging this channeling effect, bio-robotic schools may be able to maintain a schooling formation with little or no control. This flow mechanism may also be present in biological schools of tuna-like fish where it may sculpt the formations observed in nature.

  PublisherOA PDF

• Fish schools in a vertical diamond formation: Effect of vertical spacing on hydrodynamic interactions

  Physical Review Fluids · 2025-04-24 · 17 citations

  articleSenior author

  Fish schooling is believed to provide benefits by allowing individuals to leverage vortices generated by nearby fish, thereby improving their performance. While prior works have characterized horizontal planar formations of fish, our comprehensive analysis of the hydrodynamics in the vertical diamond formation reveals significant interactions among vertically arranged fish. In the densest vertical diamond formation, fin-fin, body-body, wake-body, and wake-fin interactions enhance force generation and propulsive efficiency for each individual in the school. The findings of this study could guide school configurations that enhance the performance of fish-inspired bio-robotic swarms.

  PublisherDOI

• Hydrodynamic Interactions Between Schooling Fish in a Three-Dimensional Non-Planar Cluster

  2025-07-27

  articleSenior author

  Abstract Schooling fish can fall into many different positions relative to their neighbors, resulting in different hydrodynamic interactions. Fish in large schools have been observed to share similar frontal planes relative to their neighbors, especially those at the front of the school, and differ from each other in their depths. In this work, we analyze two frontal triangular formations: side triangle (ST) and downward triangle (DT). In these formations the neighbors share the same frontal plane (same streamwise position) but vary in depth. In our prior study of the side-by-side interactions between neighbors, the undulating phase difference between the nearest laterally separated neighbors heavily impact the propulsive performance of the swimmers. Thus, in this study, we varied the phase difference between nearest lateral neighbors, between values of 0 and π, to analyze the in-phase and anti-phase modes of interaction. We conducted three-dimensional (3D) direct numerical simulations (DNS) on the frontal triangle formations using an immersed-boundary method (IBM). At a Reynolds number of 4000, we ensured grid-independent result. Through our simulations we find that the anti-phase interactions between neighbors allowed each swimmer to achieve 16% and 18% higher thrust on average in the DT and ST schools, respectively. Additionally, through the ST school, it is found that the nearest vertically separated neighbors can enhance the tail leading-edge vortices (LEV) of each other, and thus enhance their tail thrust.

  PublisherDOI

• An Untethered Bioinspired Robotic Tensegrity Dolphin with Multi-Flexibility Design for Aquatic Locomotion

  2025-04-22 · 3 citations

  article

  This paper presents the first steps toward a soft dolphin robot using a bio-inspired approach to mimic dolphin flexibility. The current dolphin robot uses a minimalist approach, with only two actuated cable-driven degrees of freedom actuated by a pair of motors. The actuated tail moves up and down in a swimming motion, but this first proof of concept does not permit controlled turns of the robot. While existing robotic dolphins typically use revolute joints to articulate rigid bodies, our design – which will be made opensource – incorporates a flexible tail with tunable silicone skin and actuation flexibility via a cable-driven system, which mimics muscle dynamics and design flexibility with a tunable skeleton structure. The design is also tunable since the backbone can be easily printed in various geometries. The paper provides insights into how a few such variations affect robot motion and efficiency, measured by speed and cost of transport (COT). This approach demonstrates the potential of achieving dolphin-like motion through enhanced flexibility in bio-inspired robotics.

  PublisherDOI

Recent grants

• Collaborative Research: Flying Snakes: Fluid Mechanics of Deforming Articulated Bodies

  NSF · $160k · 2020–2024

• CAREER: An Integrated Study of Biological Fluid Dynamics in Nature

  NSF · $193k · 2012–2017

• Collaborative Research: Fluid Dynamics-based analysis towards control of sleep apnea

  NSF · $245k · 2016–2020

• CPS: Medium: Collaborative Research: Towards optimal robot locomotion in fluids through physics-informed learning with distributed sensing

  NSF · $333k · 2020–2022

Frequent coauthors

• Junshi Wang

  80 shared

• George Lauder

  Harvard University

  67 shared

• Yan Ren

  Inner Mongolia University of Science and Technology

  65 shared

• Geng Liu

  Baidu (China)

  45 shared

• Pan Han

  39 shared

• Chengyu Li

  Villanova University

  37 shared

• Otar Akanyeti

  Aberystwyth University

  37 shared

• Alison James

  36 shared

Labs

• Dong Research GroupPI

Education

• Ph.D., Aerospace Engineering

  UCLA

  2003

Awards & honors

• AIAA Foundation Abe M. Zarem Educator Award 2016
• APS/DFD Gallery of Fluid Motion Best Video Award 2015
• UVA MAE Teaching Award 2014
• NSF Faculty Early Career Development (CAREER) 2011
• Southwest Ohio Council for Higher Education Teaching Award 2…