Surrounding Flow Field Research Articles

Analysis and improvement of the comfort performance of a car’s indoor environment based on the predicted mean vote–predicted percentage of dissatisfied and air age

Good thermal comfort of vehicle can make the passenger comfortable and the driver attention concentration, so as to enhance the competitiveness of the products. The purpose of this article is to study the comfort performance of a car’s indoor environment. First, the integral method is used to calculate the coupled heat transfer of gas and solid, and the effects of solar radiation and wall heat radiation on the field of velocity and temperature are considered. The three-dimensional flow field and thermal environment of vehicle are simulated, and the distribution of airflow, velocity field, temperature field, and predicted mean vote and predicted percentage of dissatisfied are obtained. The results are compared with the experimental data, and the difference is less than 5%. Second, the occupant’s thermal comfort is analyzed, and the average air age is used to evaluate the air freshness. The results show that the front passengers feel medium heat, the rear passengers feel mild heat, and the air is fresh in the cabin under setting environmental conditions. Finally, the air-conditioning system is improved according to the existing problems, and the new simulation results show that the thermal comfort of the cabin has been further improved.

Analysis of the effect of blade positions on the aerodynamic performances of wind turbine tower-blade system in halt states

The unsteady flow field disturbance between the blades and tower is one of the primary factors affecting the aerodynamic performance of wind turbine. Based on the research object of a 3MW horizontal axis wind turbine which was developed independently by Nanjing University of Aeronautics and Astronautics, numerical simulation on the aerodynamic performance of wind turbine system in halt state with blades in different position was conducted using large eddy simulation (LES) method. Based on the 3D unsteady numerical simulation results in a total of eight conditions (determined by the relative position with the tower during the complete rotation process of the blade), the characteristics of wind pressure distributions of the wind turbine system and action mechanism of surrounding flow field were analysed. The effect of different position of blades on the aerodynamic performance of wind turbine in halt state as well as the disturbance effect was evaluated. Results of the study showed that the halt position of blades had significant effect on the wind pressure distribution of the wind turbine system as well as the characteristics of flow around. Relevant conclusions from this study provided reference for the wind-resistant design of large scale wind turbine system in different halt states.

Turbulence intensity measurement in the wind tunnel used for airfoil flutter investigation

The paper reports on hot wire turbulence intensity measurements performed in the entry of a suction-type wind tunnel, used for investigation of flow-induced vibration of airfoils and slender structures. The airfoil is elastically supported with two degrees of freedom (pitch and plunge) in the test section of the wind tunnel with lateral optical access for interferometric measurements, and free to oscillate. The turbulence intensity was measured for velocities up to M = 0.3 i) with the airfoil blocked, ii) with the airfoil self-oscillating. Measurements were performed for a free inlet and further with two different turbulence grids generating increased turbulence intensity levels. For the free inlet and static airfoil, the turbulence intensity lies below 0.4%. The turbulence grids G1 and G2 increase the turbulence level up to 1.8% and 2.6%, respectively. When the airfoil is free to oscillate due to fluid-structure interaction, its motion disturbs the surrounding flow field and increases the measured turbulence intensity levels up to 5%.

翼身融合体飞机气动外形设计及分析

本文根据以往翼身融合体飞机的一些设计经验，设计了一种翼身融合体飞机气动外形，并研究分析了翼身融合体飞机初始模型在不同风速和迎角的情况下的气动特性。利用CATIA生成翼身融合体飞机初始模型，由于考虑到该型飞机的具体尺寸、选用翼型以及制作重量，所以飞机的巡航速度设计为30 m/s，通过风洞实验和FLUENT计算流体力学软件计算得出初始翼身融合体飞机模型的速度云图和压力云图以及初始模型飞机周围流场分布情况，然后根据FLUENT计算流体力学软件得出的初始模型流场分布情况，确定4种在初始模型基础上经过改进的模型，分别为涡流器模型、翼梢小翼模型、鸭翼模型、平尾模型，研究经过改进的4个模型气动特性(包括升力系数，阻力系数，升阻比)随速度和迎角的影响的思路是：建立精确的改进涡流器模型、改进翼梢小翼模型、改进鸭翼模型、改进平尾模型，利用CFD计算流体力学软件计算在不同风速迎角分别从−4˚到14˚下飞机的气动特性，并分析在不同速度和迎角下的飞机的气动特性随迎角的变化规律，为今后翼身融合飞机的安全高效飞行提供理论依据。并对改进的4种模型在不同速度和迎角下的升阻比等气动特性与初始模型进行对比，再根据不同的改进模型在不同飞行状态下所具有的气动特性探讨其改进模型的用途及其发展价值。 This article based on the design experience of wing body fusion aircraft before designed a wing body fusion aircraft aerodynamic shape, and analyzed initial model of the wing fusion aircraft with different wind speed and angle of attack. In the process of research, CATIA was used to generate the initial model of wing body fusion aircraft. Taking into account the specific size of the aircraft, the choice of airfoil and for weight, the cruise speed of the aircraft is designed to be 30 m/s. Through the wind tunnel experiment and FLUENT computational fluid dynamics soft-ware calculations, we can get the initial model of wing fusion aircrafts speed cloud and pressure cloud and the distribution of the surrounding flow field. On the basis of FLUENT computational fluid dynamics software and the distribution of the surrounding flow field, four improved models based on the initial model were identified: Eddy swirl model, wingtip winglet model, canyon model, and flat tail model. This paper researched the aerodynamic performance of the four improved wing-body fusion aircraft models at different angles of attack and wind speed (including lift coefficient, drag coefficient, lift drag ratio). The idea of the impact is to establish an accurate improved swirl model, to improve the wing winglet model, to improve the duck wing model, to improve the flat tail model. The research has used CFD to calculate the aerody-namic characteristics of the airplane at different wind of angles at −4˚ to 14˚, and analyzed the aerodynamic characteristics of the aircraft at different speeds and angles of attack. It can pro-vide a theoretical basis for the safe and efficient flight of the aircraft. This research compared the aerodynamic characteristics of the improved four models with the initial model at different speeds and angles of attack. And then it used the aerodynamic characteristics of different im-proved models under different flight states to explore the use of the improved model and its development value.

Flow velocity estimation using a fish-shaped lateral line probe with product-moment correlation features and a neural network

Environmental studies on fish require measurements of highly turbulent flows in both the laboratory and in the field. A fish-shaped bioinspired flow measuring device is applied in conjunction with data processing workflow which leverages the interactions between the body and the surrounding flow field for velocity estimation in turbulent flows. Our objective is to develop a robust velocity estimation methodology relevant for studies of fish behavior using a bioinspired fish-shaped artificial lateral line probe (LLP). We show that the device is capable of covering the range of flow velocities from 0 to 1.5m/s. Three different sets of experiments performed in a closed flow tunnel, a model vertical slot fishway and laboratory open channel flume were collected and combined to provide time-averaged flow velocity and LLP measurements under fully turbulent flow conditions. Based on the experimental results, a signal processing workflow using Pearson product-moment correlation coefficient (PCC) features in conjunction with an artificial neural network (ANN) is presented. Using PCC features provides a simple data fusion methodology exploiting the use of the LLP's as a simultaneous collocated sensing array. In this work we show that (1) the PCC-ANN workflow provides the first LLP velocity estimator without repeated calibration across the full span of 0–1.5m/s, (2) using all pressure sensors results in the best performance with R2=0.917, but requires a PCC feature matrix of 55 dimensions and (3) a stepwise reduction of the PCC feature matrix allows for the use of as few as 11 dimensions, and results in R2=0.911, indicating that a modest reduction in LLP velocity estimation performance can be gained by a large reduction in dimensionality. A surprising finding was that after stepwise reduction, the best performing sensor pair combinations were not the expected pitot-like anteroposterior couples spanning from nose to body. Instead, it was found that optimal velocity estimation using the LLP exploited a network of sensor pairs. It is shown that the LLP can be implemented similar to an ADV for highly turbulent flows over the range of 0–1.5m/s, and in addition provides body-centric pressure distributions which may aid in the interpretation of fish hydrodynamic preferences in future environmental studies.

Comparison of the Average Lift Coefficient ͞CL and Normalized Lift ͞ηL for Evaluating Hovering and Forward Flapping Flight

The capability of flapping wings to generate lift is currently evaluated by using the lift coefficient C ¯ L , a dimensionless number that is derived from the basal equation that calculates the steady-state lift coefficient CL for fixed wings. In contrast to its simple and direct application to fixed wings, the equation for C ¯ L requires prior knowledge of the flow field along the wing span, which results in two integrations: along the wing span and over time. This paper proposes an alternate average normalized lift η ¯ L that is easy to apply to hovering and forward flapping flight, does not require prior knowledge of the flow field, does not resort to calculus for its solution, and its lineage is close to the basal equation for steady state CL. Furthermore, the average normalized lift η ¯ L converges to the legacy CL as the flapping frequency is reduced to zero (gliding flight). Its ease of use is illustrated by applying the average normalized lift η ¯ L to the hovering and translating flapping flight of bumblebees. This application of the normalized lift is compared to the same application using two widely-accepted legacy average lift coefficients: the first C ¯ L as defined by Dudley and Ellington, and the second lift coefficient by Weis-Fogh. Furthermore, it is shown that the average normalized lift η ¯ L has a physical meaning: that of the ratio of work exerted by the flapping wings onto the surrounding flow field and the kinetic energy available at the aerodynamic surfaces during the generation of lift. The working equation for the average normalized lift η ¯ L is derived and is presented as a function of Strouhal number, St.

Numerical study of parachute inflation process based on smoothed particle hydrodynamics fluid structure interaction method

Shortcomings in large deformation calculations by mesh-based numerical methods have been overcome by smoothed particle hydrodynamics method, which is a new meshless algorithm based on Lagrange description and has been widely used in simulations as blasting and impacting, but not been applied in research of engineered fabrics yet. In this paper, a fluid structure interaction method coupling smoothed particle hydrodynamics and finite element was proposed, by which the inflating process of a model parachute was investigated. In the modeling of parachute, the same nodes were shared by beam elements of reinforced belts and adjacent canopy elements to simulate the elastic constraints, while the parachute meshes model was adjusted to satisfy requirement of fluid structure interaction calculation by loading internal pressure, and surrounding flow field was described by smoothed particle hydrodynamics particles. Then, the fluid structure interaction calculating could be realized by contacting algorithm between particles and mesh nodes. The dynamic processes of expanding structure and flow field were obtained by this method. According to the analysis of numerical results, the parachute inflating process could be divided into pre-inflating stage, fully inflating stage and inflated stage; moreover, the noise occurred in wind tunnel experiment could be explained by this method. The “breathing” phenomenon and top collapsing of canopy appeared in numerical results, as corresponded to the tunnel experiment. This new method could be a good supplement in parachute design and research.

Examination of Drying Behavior of Mung Bean in Laboratory and the Establishment of the Corresponding Rea Model

Drying is an essential preservation technique for agricultural products. It also provides longer shelf life and light-weight for cost-effective transportation. The ability to describe drying of the agricultural products accurately is known to be important. Designing and optimization of drying operations ideally needs a simple, accurate yet mechanically meaningful model. Most published studies have employed diffusion-based models to describe drying kinetics which requires solution of partial differential equation and substantial amount of work to determine diffusivity function. Reaction Engineering Approach (REA) is a simple alternative to the more complex approaches. It can take a lumped form which can be implemented in computational fluid dynamics (CFD) for coupling of objects being dried and surrounding flow field. In this study, moist mung bean was dried in a range of pre-set constant drying conditions and the appropriate REA parameters were obtained. The changes of temperature and moisture content of mung bean samples during drying were measured experimentally and the results were compared with the REA model calculations. The model predictions were in very good agreement with the experimental data under all the conditions tested. The agreement of moisture content was revealed by R2 higher than 0.991 and RMSE lower than 0.003. The agreement of particle temperature was also revealed by R2 higher than 0.932 and RMSE lower than 0.08. Based on the experimental data, REA model was established for the necessary parameters. The REA model has been shown to represent the experimental drying data very well. Practical Applications Mung bean is an important legume of Asian origin, now widely cultivated throughout Asia, Australia, New Zealand and Africa. It contains a number of essential fatty acids, antioxidants minerals and proteins that are known to reduce the risk of coronary heart disease, diabetes and obesity, and can considerably lower blood cholesterol. Most of mung beans are dried and only small amounts are consumed fresh. With the fast, effective and economical technique to reduce the moisture content of materials, for better storage and transportation, mung bean are dried usually using appropriate machinery (such as fluid bed dryer). The ability to describe drying of these products quantitatively for better designs of the drying facilities urges the necessity of developing an appropriate drying model for dehydrating of mung beans. The basic aim of this article was to present a new mathematical model to describe drying kinetics of mung bean and establish the corresponding REA model. The established model parameters would be applied in fluid bed drying modeling.

Drag and heat reduction mechanism induced by a combinational novel cavity and counterflowing jet concept in hypersonic flows

The drag and heat reduction problem of hypersonic reentry vehicles has always attracted the attention worldwide, and many novel schemes have been proposed recently. In the current study, the research progress of the combinational configuration of the forward-facing cavity and the counterflowing jet has been reviewed, and the conventional cavity configuration has been substituted by an approximate maximum thrust nozzle contour for better heat and surface pressure reduction efficiency. The Reynolds-average of Navier-Stokes (RANS) equations coupled with the SST k–ω turbulence model have been employed to calculate its surrounding flow fields. A validation metric and the grid convergence index (GCI) have been employed to conduct the turbulence model assessment and the grid independence analysis respectively. The axisymmetric assumption has been verified by three-dimensional computational results as well. The obtained results show that the SST k-ω model is more suitable for the novel drag and heat flux reduction scheme proposed in this article, and the axisymmetric assumption is approximately reasonable. After investigating the influence of jet pressure ratio, the novel combinational configuration has been verified to be more effective in heat and surface pressure reduction, and this is because the approximate maximum thrust nozzle contour contributes to better expansion and avoids total pressure loss of the jet.

Hydrodynamic influences of artificial cilia beating behaviors on micromixing

In microfluidic applications, the beating behaviors of artificial cilia determine the efficacy of artificial cilia-based micromixers. The same is especially true when the rapid mixing of two fluids with artificial cilia actuation is highly demanded in many biomedical and analytical chemistry contexts. The transient hydrodynamics induced by the diversely dynamic motions of artificial cilia and the associated interactions with surrounding flow fields engender speculation for identifying an ideal trajectory of artificial cilia in an effective micromixing process. Intrigued by this motive, we selected four distinct beating behaviors for comparing micromixing performance. The tangled interactions between the induced flow by artificial cilia and the imposing flow through syringe pump actuation were also documented. A parametric study was performed via a micro-particle image velocimetry technique to elucidate the synergic effects contributed by dominant parameters, such as the beating speed and patterns of artificial cilia. Depth-resolved induced flow patterns through artificial cilia actuation were provided using a computational fluid dynamic method to elucidate how micromixing was achieved in a whole-field point of view. A new microscale flow mixing concept was therefore initiated and demonstrated in this work to extend the current practices related to artificial cilia-based micromixers for highly viscous flow manipulation applications.

A three‐dimensional computational fluid dynamics model of shear stress distribution during neotissue growth in a perfusion bioreactor

Bone tissue engineering strategies use flow through perfusion bioreactors to apply mechanical stimuli to cells seeded on porous scaffolds. Cells grow on the scaffold surface but also by bridging the scaffold pores leading a fully filled scaffold following the scaffold's geometric characteristics. Current computational fluid dynamic approaches for tissue engineering bioreactor systems have been mostly carried out for empty scaffolds. The effect of 3D cell growth and extracellular matrix formation (termed in this study as neotissue growth), on its surrounding fluid flow field is a challenge yet to be tackled. In this work a combined approach was followed linking curvature driven cell growth to fluid dynamics modeling. The level-set method (LSM) was employed to capture neotissue growth driven by curvature, while the Stokes and Darcy equations, combined in the Brinkman equation, provided information regarding the distribution of the shear stress profile at the neotissue/medium interface and within the neotissue itself during growth. The neotissue was assumed to be micro-porous allowing flow through its structure while at the same time allowing the simulation of complete scaffold filling without numerical convergence issues. The results show a significant difference in the amplitude of shear stress for cells located within the micro-porous neo-tissue or at the neotissue/medium interface, demonstrating the importance of taking along the neotissue in the calculation of the mechanical stimulation of cells during culture.The presented computational framework is used on different scaffold pore geometries demonstrating its potential to be used a design as tool for scaffold architecture taking into account the growing neotissue. Biotechnol. Bioeng. 2015;112: 2591-2600. © 2015 Wiley Periodicals, Inc.

Toward efficient navigation in uncertain gyre-like flows

We present the development and experimental validation of an autonomous surface/underwater vehicle control strategy that leverages the environmental dynamics and uncertainty to navigate in a stochastic fluidic environment. We assume that the workspace is composed of the union of a collection of disjoint regions, each bounded by Lagrangian coherent structures (LCSs). LCSs are dynamical features in the flow field that behave like invariant manifolds in general time-invariant dynamical systems and delineate the boundaries of attraction basins. We analyze a passive particle’s noise-induced transition between adjacent LCS-bounded regions and show how most probable escape trajectories with respect to the transition probability between adjacent LCS-bounded regions can be determined. Additionally, we show how the likelihood of transition can be controlled through minimal actuation. The result is an energy efficient navigation strategy that leverages the inherent dynamics of the surrounding flow field for mobile sensors operating in a noisy fluidic environment. We experimentally validate the proposed vehicle control strategy and analyze its theoretical properties. Our results show that the single vehicle control parameter exhibits a predictable exponential scaling with respect to the escape times and is effective even in situations where the structure of the flow is not fully known and control effort is costly.

Large-Eddy Simulation of Aircraft Wake Evolution from Roll-Up Until Vortex Decay

The evolution of aircraft wake vortices from the roll-up until vortex decay is studied by large-eddy simulation. An aircraft model and the surrounding flow field obtained from high-fidelity Reynolds-averaged Navier–Stokes simulation are swept through a ground-fixed computational domain to initialize the wake. After the wake initialization a large-eddy simulation of the vortical wake is performed until vortex decay. In this paper the methodology is tested with a NACA 0012 wing and applied to the DLR-F6 wing-body model in cruise condition and a long-range aircraft model in high-lift configuration which was used in the European Aircraft Wing with Advanced Technology Operation project. The correlation between the detailed roll-up process of the vorticity sheet shedding from the main wing and the characteristics of the rolled-up vortex pair such as vortex circulation, core radius, and separation is investigated with and without ambient turbulence. In both the DLR-F6 wing-body and the long-range aircraft models, the behavior of the formed vortex pair appears similar to that of a vortex pair defined by an analytical vortex model including the impact of ambient turbulence on vortex linking and decay. The velocity profile of a fully rolled-up vortex pair at around agrees well with the Rosenhead–Burnham–Hallock vortex model.

The Effect of Orifice Plate on Flow Field and Thermal Environment in Oven Box

Air velocity in oven box is an important factor. The value of air velocity will affect the result of drying. This paper use the method of numerical simulation to research the effect of orifice plate on flow field and thermal environment in oven box. The results show the change rate of thermal environment & air flow field in oven box is depend on supply air volume, and the use of orifice plate will affect the flow field obviously.

Aerodynamic and aerothermodynamic analysis of high-speed earth re-entry capsule

This paper deals with the computational fluid dynamics analysis of a capsule entering the earth atmosphere at the end of a sample return mission. Several numerical simulations have been carried out to assess the flowfield environment past a sphere-cone capsule, by using non-equilibrium reacting gas approximations. Heat shield ablation and effects of flow plasma radiation on capsule aeroheating are also accounted for in the flowfield analysis. The issue of aerodynamic and aerothermodynamic performance of the entry spacecraft in the framework of a super-orbital re-entry scenario is addressed.

Formation and post-formation dynamics of bacterial biofilm streamers as highly viscous liquid jets.

It has been recently reported that in presence of low Reynolds number (Re ≪ 1) transport, preformed bacterial biofilms, several hours after their formation, may degenerate in form of filamentous structures, known as streamers. In this work, we explain that such streamers form as the highly viscous liquid states of the intrinsically viscoelastic biofilms. Such “viscous liquid” state can be hypothesized by noting that the time of appearance of the streamers is substantially larger than the viscoelastic relaxation time scale of the biofilms, and this appearance is explained by the inability of a viscous liquid to withstand external shear. Further, by identifying the post formation dynamics of the streamers as that of a viscous liquid jet in a surrounding flow field, we can interpret several unexplained issues associated with the post-formation dynamics of streamers, such as the clogging of the flow passage or the exponential time growth of streamer dimensions. Overall our manuscript provides a biophysical basis for understanding the evolution of biofilm streamers in creeping flows.

충격파 터널을 이용한 고속추진기관 시험 연구

충격파 터널은 초음속 및 극초음속 비행조건의 유동장을 지상에서 가장 유사하게 모사할 수 있는 시험설비로서, 거의 반세기 동안 전 세계적으로 유용하게 운용되고 있다. 국내의 극초음속 비행체에 대한 많은 관심의 결과로 충격파 시험장치에 대해 주목하고 있으며, 최근에 KAIST에서는 중간 크기의 충격파 터널을 갖추게 되었다. 본 논문은 개발된 충격파 터널의 성능과 최근 수행된 모델 스크램제트 시험자료를 제시하고 있다. 본 연구에서 모사된 자유흐름 유동조건은 마하수 5.7 비행속도에 해당하며, 이러한 비행조건에서 스크램제트의 초음속 연소기내에 유동 환경을 모사하였다. Shock tunnels are known to be capable of simulating flow-field environments of supersonic and hypersonic flights. They have been operated successfully world-wide for almost half a century. As a consequence of the strong interest in hypersonic vehicles in Korea, attention has been given on this type of facility and so an intermediate-sized shock tunnel has lately been built at KAIST. In the light of this, this paper presents our tunnel performance and some of the model scramjet test data. The freestream flow used in this work replicates a supersonic combustor environment for a Mach 5.7 flight speed.

Rendering technique of multi-layered domain boundaries and its application to fluid flow in porous media visualizations

Current visualization techniques for computational fluid dynamics applications are sophisticated and work well in simple geometries. For complex geometries such as pore spaces, multiple domain boundaries obstruct the view and make the studying of fluid flow fields difficult. To overcome these deficiencies, we use two-sided materials to render the domain boundaries. Using this technique, it is possible to place the camera inside the domain and have a non-obstructed view of the surrounding flow field without losing spatial reference to the domain boundaries. As a result, a larger part of fluid flow visualization is visible. Two-sided material rendering was successfully applied to display still images with Blender Cycles renderer, in a virtual reality environment, and several implementation techniques were explored for using the Visualization Toolkit.

Inducing 3D vortical flow patterns with 2D asymmetric actuation of artificial cilia for high-performance active micromixing

Driven by the advancement of the “lab-chip” concept, a new beating behavior of artificial cilia was identified to meet the demands on rapid and complete fluid mixing in miniaturized devices. This beating behavior is characterized by an in-plane asymmetric motion along a modified figure-of-eight trajectory. A typically symmetric figure-of-eight motion was also tested for comparison. Results showed that with this new beating behavior, the mixing efficiency for complete mixing is 1.34 times faster than that with the typical figure-of-eight motion. More importantly, the required beating area was only approximately two-thirds of that in the typical figure-of-eight motion, which is beneficial for more compact designs of various “lab-chip” applications. The unique planar asymmetric motion of the artificial cilia, which enhanced the magnitudes of the induced three-dimensional (3D) flow, was identified by micro-particle image velocimetry (µPIV) measurement and numerical modeling as a major contributor in enhancing microscale mixing efficiency. Quantitatively, 3D vortical flow structures induced by the artificial cilia were presented to elucidate the underlying interaction between the artificial cilia and the surrounding flow fields. With the presented quantification methods and mixing performance results, a new insight is provided by the hydrodynamic advantage of the presented micromixing concept on efficiently mixing highly viscous flow streams at microscale, to leverage the attributes of artificial cilia in the aspect of microscale flow manipulation.

Lipid Shedding from Single Oscillating Microbubbles

Lipid-coated microbubbles are used clinically as contrast agents for ultrasound imaging and are being developed for a variety of therapeutic applications. The lipid encapsulation and shedding of the lipids by acoustic driving of the microbubble has a crucial role in microbubble stability and in ultrasound-triggered drug delivery; however, little is known about the dynamics of lipid shedding under ultrasound excitation. Here we describe a study that optically characterized the lipid shedding behavior of individual microbubbles on a time scale of nanoseconds to microseconds. A single ultrasound burst of 20 to 1000 cycles, with a frequency of 1 MHz and an acoustic pressure varying from 50 to 425 kPa, was applied. In the first step, high-speed fluorescence imaging was performed at 150,000 frames per second to capture the instantaneous dynamics of lipid shedding. Lipid detachment was observed within the first few cycles of ultrasound. Subsequently, the detached lipids were transported by the surrounding flow field, either parallel to the focal plane (in-plane shedding) or in a trajectory perpendicular to the focal plane (out-of-plane shedding). In the second step, the onset of lipid shedding was studied as a function of the acoustic driving parameters, for example, pressure, number of cycles, bubble size and oscillation amplitude. The latter was recorded with an ultrafast framing camera running at 10 million frames per second. A threshold for lipid shedding under ultrasound excitation was found for a relative bubble oscillation amplitude >30%. Lipid shedding was found to be reproducible, indicating that the shedding event can be controlled.