Implicit large eddy simulation of acoustic loading in supersonic turbulent boundary layers

This paper investigates the accuracy of implicit Large Eddy Simulation in the prediction of acoustic phenomena associated with pressure fluctuations within a supersonic turbulent boundary layer. We assess the accuracy of implicit Large Eddy Simulation against Direct Numerical Simulation and experiments for attached turbulent supersonic flow with zero-pressure gradient, and further analyze and discuss the effects of turbulent boundary layer pressure fluctuations on acoustic loading both at the high and low frequency regimes. The results of high-order variants of the simulations show good agreement with theoretical models, experiments, as well as previously published Direct Numerical Simulations

Computational aeroacoustics beneath high speed transitional and turbulent boundary layers

This paper concerns a study of pressure fluctuations beneath hypersonic shock-wave turbulent boundary layer interactions and the associated acoustic loading on a compression/expansion ramp. Using high-order methods, we have performed Direct Numerical Simulations at Mach 7.2. We compare the spectral analysis of the pressure fluctuations at various locations of the compression/expansion ramp with the spectra calculated beneath a hypersonic transitional boundary layer. Similarities and differences between the two hypersonic boundary layers, in the context of acoustic loading, are drawn. Extremely high values of pressure fluctuations are recorded after the shock re-attachment where we also observe the maximum pressure gradients indicating that acoustic loading is correlated with areas of high-pressure gradients. Finally, we discuss the impact of the boundary layer state (attached flow, turbulence bursts, recirculations, shock oscillations, shock re-attachment and expansion fans) on the frequency spectrum of the pressure fluctuations

Wavelet analysis of high-speed transition and turbulence over a flat surface

This paper presents a study of high speed boundary layers using the wavelet method. We analyze direct numerical simulation data for high-speed, compressible transitional, and turbulent boundary layer flows using orthogonal anisotropic wavelets. The wavelet-based method of extraction of coherent structures is applied to the flow vorticity field, decomposed into coherent and incoherent contributions using thresholding of the wavelet coefficients. We show that the coherent parts of the flow, enstrophy spectra, are close to the statistics of the total flow, and the energy of the incoherent, noise-like background flow is equidistributed. Furthermore, we investigate the distribution of the incoherent vorticity in the transition and turbulent regions and examine the correlation with the near-wall pressure fluctuations. The results of our analysis suggest that the incoherent vorticity part is not a random "noise"and correlates with the actual noise emanating from inside the boundary layer. This could have implications regarding our understanding of the physics of compressible boundary layers and the development of engineering models

What Are You Looking At? Team Fight Prediction Through Player Camera

Esport is a large and still growing industry with vast audiences. Multiplayer Online Battle Arenas (MOBAs), a sub-genre of esports, possess a very complex environment, which often leads to experts missing important coverage while broadcasting live competitions. One common game event that holds significant importance for broadcasting is referred to as a team fight engagement. Professional player's own knowledge and understanding of the game may provide a solution to this problem. This paper suggests a model that predicts and detects ongoing team fights in a live scenario. This approach outlines a novel technique of deriving representations of a complex game environment by relying on player knowledge. This is done by analysing the positions of the in-game characters and their associated cameras, utilising this data to train a neural network. The proposed model is able to both assist in the production of live esport coverage as well as provide a live, expert-derived, analysis of the game without the need of relying on outside sources

Toxicity bioassay of waste cooking oil-based biodiesel on marine microalgae

The world biodiesel production is increasing at a rapid rate. Despite its perceived safety for the environment, more detailed toxicity studies are mandatory, especially in the field of aquatic toxicology. While considerable attention has been paid to biodiesel combustion emissions, the toxicity of biodiesel in the aquatic environment has been poorly understood. In our study, we used an algae culture growth-inhibition test (OECD 201) for the comparison of the toxicity of B100 (pure biodiesel), produced by methanol transesterification of waste cooking oil (yellow grease), B0 (petroleum diesel fuel) and B20 (diesel-biodiesel blended of 20% biodiesel and 80% petroleum diesel fuel by volume). Two marine diatoms Attheya ussuriensis and Chaetoceros muelleri, the red algae Porphyridium purpureum and Raphidophyte Heterosigma akashiwo were employed as the aquatic test organisms. A sample of biodiesel from waste cooking oil without dilution with petroleum diesel (B100) showed the highest level of toxicity for the microalgae A. ussuriensis, C. muelleri and H. akashiwo, compared to hexane, methanol, petroleum diesel (B0) and diluted sample (B20). The acute EC50 in the growth-inhibition test (96 h exposure) of B100 for the four species was in the range of 3.75–23.95 g/L whereas the chronic toxicity EC50 (7d exposure) was in the range of 0.42–16.09 g/L

Emphysematous cholecystitis: a case report

A 65-year-old Greek man with a history of diabetes mellitus and hypertension was admitted because of right upper quadrant pain, nausea and palpable right quadrant mass. On admission the patient was febrile (38.8°C) with a total bilirubin level of 1.99 mg/dl (direct 0.59 mg/dl); SGOT 1.26 mg/dl; Na 135 mmol/l and K 2.9 mmol/l. The white blood count was 15200/μl with 92.2% neutrophiles. Axial sections of single slice CT imaging (section thickness 10 mm), revealed emphysematous cholecystitis with thickening of gallbladder wall and wall enhancement after iv contrast enhancement, as well as, dilatation of the gallbladder with multiple gallstones precipitate and intraluminal air. The patient underwent subtotal cholecystectomy and a cholecystostomy was placed. The culture of the bile showed positivity to toxin A of Clostridium Difficile and to Escherichia Coli. The postoperative course of the patient was uneventful

UCNS3D: An open-source high-order finite-volume unstructured CFD solver

UCNS3D is an open-source computational solver for compressible flows on unstructured meshes. State-of-the-art high-order methods and their associated benefits can now be implemented for industrial-scale CFD problems due to the flexibility and highly-automated generation offered by unstructured meshes. We present the governing equations of the physical models employed in UCNS3D, and the numerical framework developed for their solution. The code has been designed so that extended to other systems of equations and numerical models is straightforward. The employed methods are validated towards a series of stringent well-established test problems against experimental or analytical solutions, where the full capabilities of UCNS3D in terms of applications spectrum, robustness, efficiency, and accuracy are demonstrated.European Union funding: 314139, 653838 and 823767. Engineering and Physical Sciences Research Council (EPSRC): EP/L000261/1, EP/P020259/1, EP/G069581/1, EP/T518104/1 and 13794 Innovate UK: 26326