- Post Doctoral
MIT Unit Affiliation:
- Mechanical Engineering
Post Doc Sponsor / Advisor:
Date PhD Completed:
Top 3 Areas of Expertise:
Expected End Date of Post Doctoral Position:
Large wave formation in multiphase flow pipe/channel flows:
I carried out research in the fields of nonlinear interfacial wave dynamics, analytical methods and computational fluid dynamics for the purpose of predictinh large nonlinear rogue waves and slugs in oil pipelines with emphasis on enhancing subsea pipeline flow assurance. During this investigation, I developed both theoretical, numerical methods (finite volume, finite difference, spectral and interface tracking schemes) and models from experimentally data which were able to provide new insights into slug formation and their prediction within horizontal channels and pipes. This work was advised by Dr. Yuming Liu in the Vortical Flow Research Lab (September 2007 - Present)
Investigation of structural-accoustic coupling of musical instruments:
For this project, I carried out theoretical and numerical investigations to determine the impact of structural-acoustic coupling on the performance and efficiency of various stringed instruments. I developed fully coupled Abaqus finite element models for the direct simulation of instrument response. This work was advised by Professor Nicholas Makris in the Laboratory for Undersea Remote Sensing (April 2016 - Present)
Boundary-element modeling of underwater acoustics using direct simulations
on HPC platforms:
This work examined the effectiveness of using a massively parallel boundary element numerical algorithim for the prediction of underwater acoustics. Traditional work in this field has relied on theoretical models for specific ocean enviornments and specilized numerical algorithms developed individual scattering objects within the domain. While these method may be accurate for their particular problem of interest, there has been issues in extending these methods to more generalized subsea objects of different ocean enviornments (deep vs. shallow water, nonlinear surface wave fields vs. idealize flat interface, muddy sea floor vs. simple rigid boundary). In this work, I developed a general boundary-element acoustic solver that was capable of direct simulation of complex scattering geometries within general ocean environments. Comparisons between this new method and existing numerical and experimental results have shown excellent agreement.
Many industrial applications involve the transport of multiphase flows through pipes. For instance, the design and operation of oil pipelines and production facilities relies heavily on understanding the hydrodynamics of multiphase flow. Industrial engineers utilizes multiphase flow simulators to aid in the design and flow assurance of such systems; however, the complexity of the physics and the range of scales involved in the problem require that the numerical algorithms invoke phase averaging methods and rely on empirical models. These assumptions and simplifications often result in predictions which are non-physical or are off by orders of magnitude forcing engineers to implement conservative safety factors to accommodate the large uncertainties. The development of physics based models may reduce the empiricism in the simulators allowing for the creation of more robust and cost effective designs.
The work described in this thesis carries out both theoretical and computational investigations of some nonlinear mechanisms governing the interfacial stability and nonlinear evolution of stratified two-phase flows through horizontal channels and pipes. The resulting investigation identifies a strong nonlinear energy transfer mechanism which extracts energy generated by an interfacial instability and transfers it (with possible bi-exponential growth rates) to long wavelength waves which may eventually evolve into large amplitude waves and slugs. Detailed investigations demonstrate the effectiveness of this mechanism in flows ranging from ideal (potential) to turbulent two-phase flows. This thesis consists of three key focus areas.
The first section develops a nonlinear potential flow analysis to identify a mechanism composed of a triad of resonantly interacting interfacial waves which are influenced by the Kelvin-Helmholtz interfacial instability. The mechanism that is identified permits the rapid energy transfer from linearly unstable short waves to stable long waves through nonlinear resonant wave interactions. It was found that, depending on the flow conditions, it is possible for linearly stable waves to achieve bi-exponential growth due to the resonant coupling. Extensions of this mechanism to broadbanded wave interactions were found to be in close agreement with experimental measurements. The analysis was also adjusted to examine the special case of sub-harmonic resonant interactions which have been observed in many experimental measurements and it was shown that this special case could still effectively create rapid long wave growth with up to bi-exponential growth rates.
The second focus area examines the robustness of the aforementioned potential flow mechanism by identifying if a linear interfacial instability could be effectively coupled with resonant interactions in the presence of viscosity and flow turbulence. Using a linear stability analysis along with direct numerical simulations, comparisons were made against experimental measurements. This analysis was able to accurately identify the bandwidth of unstable interfacial modes as well as predict the existence of the strong sub-harmonic and triad resonances among modes which were reported in the experimental observations. The behavior observed in the numerical simulations demonstrates that the coupled instability-resonance mechanism is capable of existing in more complex two-phase turbulent flows and still permits the rapid exchange of energy from unstable short to linearly stable long wavelength modes. In addition, the numerical simulation results provide high-resolution data sets for which the interfacial stress distributions could quantified and described providing insights into the necessary behavior of future interfacial stress modeling.
The final focus area is dedicated to developing a novel nonlinear slug transition criterion which couples the effects of a linear instability with that of nonlinear resonant interaction theory. An energy bounding condition is proposed for which the number of resonant modes which are linearly unstable is minimized allowing for a critical gas velocity to be identified. Comparisons are made against experiments carried out in horizontal channels and good agreement is observed. A heuristic method is proposed which allows for "equivalent" channel flow conditions to be obtained which are representative of the original pipe flow conditions. Unlike previously developed slug transition conditions, this new nonlinear criterion provides predictions which are significantly more accurate when compared against experimental measurements and maintains its accuracy over a large range of pipe diameters, flow conditions, and fluid combinations.
Top 5 Awards and honors (name of award, date received):
5 Recent Papers:
Li, C., Campbell, B. K., Liu, Y. Boundary-element modeling of underwater acoustics using direct simulations on HPC platforms. J. Acoust. Soc. Am. (In Preparation)
Campbell, B. K., Liu, Y. Nonlinear coupling of interfacial instabilites with resonant wave interactions in horizontal two-fluid plane Poiseuille/Couette flows: numerical and experimental observation. J. Fluid Mech. (Under Review).
Campbell, B. K., Liu, Y. A nonlinear transition criterion for the prediction of the onset of slugging in horizontal channels and pipes. Physics of Fluids. (Accepted).
Campbell, B. K., Liu, Y. Sub-harmonic resonant interactions in the presence of a linear interfacial instability. Physics of Fluids. 26, 082107(2014).
Campbell, B. K., Liu, Y. Nonlinear resonant interactions of interfacial waves in horizontal stratified channel flows. J. Fluid Mech. 717, 612-642 (2013).