0704-883-0675     |      dataprojectng@gmail.com

SIMULATION AND THEORETICAL STUDY OF SWIMMING AND RESISTIVE FORCES WITHIN GRANULAR MEDIA

  • Project Research
  • 1-5 Chapters
  • Abstract : Available
  • Table of Content: Available
  • Reference Style: APA
  • Recommended for : Student Researchers
  • NGN 5000

ABSTRACT.

One way to investigate the physics of a medium is to study the forces on intruders moving through the media. A special case of intruders moving in media is the locomotion of organisms. Locomotion within fluids (flying in air and swimming in water) has been extensively studied and the complexity of interaction between intruders and fluids is well recognized. Locomotion within yielding substrates like sand, soil and debris that display both solid and fluid-like behavior has been less studied and is therefore less understood than to locomotion within fluids or on solid ground. In such materials, validated theories for describing the flow and resistive forces on intruders have not reached the levels of those for fluids. As a representative case of subsurface locomotion in granular media, we study on the undulatory sand-swimming of the sandfish lizard (Scincus scincus), a small (∼10 cm) desertdwelling lizard. We use numerical simulations and theoretical models of the interactions between granular media and simple objects, biological and robotic systems to reveal principles of undulatory locomotion in granular media. We also use the models to investigate the resistive forces on intruders with different orientations and shapes, which is essential for the understanding of locomotion ability and performance of locomotors. Previous experimental work using high speed x-ray imaging showed that the sandfish lizard swims within dry granular media without limb use by propagating a single period traveling sinusoidal wave along its body. The wave efficiency η, the ratio of the forward speed to the traveling wave speed, was approximately 0.5, independent of the packing state of the media (close and loose). To explain these results, we develop a resistive force model with empirical force laws to explain the swimming speed observed in the animal experiment. We show that the higher wave efficiency reached by the sandfish compared to the low Re swimmers (∼ 0.2) was because of the different functional form of the resistive forces on a rod dragged in granular media. We vary the ratio of undulation amplitude (A) to wavelength (λ) and demonstrate that an xii optimal waveform A/λ ≈ 0.2 for sand-swimming exists, which results from the competition between η and λ. To test assumptions in RFT and to study more detailed mechanics of sand-swimming, we developed a numerical model of the sandfish coupled to a discrete element method simulation of the granular medium. The numerical model confirmed that inertial forces are negligible and that the forces on the animal can be approximated by the forces on rods dragged at constant speed in granular media. The wave efficiency predicted by simulation qualitatively matched both the RFT model and the prediction of the optimal A/λ; However, the simulation revealed that the RFT over predicted the swimming speed because the reduction in magnitude of the resistive forces during velocity reversal was not considered. The RFT model and simulation helped the development of a sand-swimming robot, and the robot verified predictions from the RFT model and the simulation, such as the value of the wave efficiency, the actuator torque, and the effect of varying kinematic parameters including A/λ and number of periods. Inspired by the shovel-shaped head of the sandfish lizard, we studied the drag induced lift in granular media. We found that when a submerged intruder moves at a constant speed within a granular medium it experiences a lift force whose sign and magnitude depend on the intruder shape. We demonstrated that the lift forces and hence vertical position of the sand-swimming robot as it moves forward within granular media can be controlled by varying its head shape. The models together with robots explained biological observations of the kinematics of the animal and provide a hypothesis for the morphological adaptation (head shape) of the animal as well as guidance for building biophysically inspired robot that could explore challenging environments. The principles learned about the resistive forces can also help the design of the other machines that interact with granular media. My studies have given new insights into localized intrusion of simple and complex/composite shapes in granular media.





Related Project Materials

An evaluation of translation accuracy in Hausa language subtitling for Nollywood films in Kano

Background of the study
This study evaluates the accuracy of translation in Hausa language subtitling for Nollywood films...

Read more
An empirical study of strategic flexibility and its impact on business resilience: A case study of SMEs in Kano State.

Background of the Study: Strategic flexibility refers to a firm’s ability to adapt and respond to changes in its environment, market conditio...

Read more
The influence of sustainable marketing practices on customer engagement: Evidence from an eco-friendly product in Port Harcourt, Nigeria

Background of the study

Sustainable marketing practices have increasingly become pivotal in the modern business environment, particularly...

Read more
The role of faith-based organizations in providing mental health support to older adults in Benue State

Background of the Study

Faith-based organizations (FBOs) play a pivotal role in many communities by providing spiritual guidance, social...

Read more
STYLISTIC ANALYSIS OF CHIMAMANDA NGOZI ADICHIE’S HALF OF A YELLOW SUN

ABSTRACT

This study is a stylistic analysis of Chimamanda Ngozi Adichie‟s novel Half Of A Yellow Sun, which comprises four parts with a t...

Read more
An appraisal of informal education’s effectiveness in preparing students for civic engagement in Ningi Local Government Area, Bauchi State

Background of the Study
Civic engagement is a cornerstone of a vibrant democracy, requiring active participation and infor...

Read more
The impact of interest rate variability on deposit growth in banking: a case study of Fortis Microfinance BankThe impact of interest rate variability on deposit growth in banking: a case study of Fortis Microfinance Bank

Background of the Study

Interest rate variability is a critical determinant of deposit growth in the banking sector. Fortis Microfinance...

Read more
The Effect of Government Digital Policies on Innovation Adoption in Nigeria

Background of the Study
Government digital policies have become critical instruments for steering innovation adoption acro...

Read more
An Examination of Consonantal Patterns in Yoruba: Implications for Speech Recognition Technology in Nigeria

Background of the study

Yoruba, a major Nigerian language known for its distinct phonological characteristics, exhibits unique consonanta...

Read more
An assessment of debit transaction fee structures on consumer spending in banking: a case study of United Bank for Africa

Background of the Study:
Debit transaction fee structures are critical components of a bank’s revenue model and can s...

Read more
Share this page with your friends




whatsapp