Energy Content Research Articles

Centrifugal Compressor Surge in Innovative Heat Pump: Fluid Dynamic and Vibrational Analysis

Abstract In the current energy scenario, it is necessary to reduce fossil fuel consumption to achieve the far-sighted and stringent decarbonization goals. To date, heat is mainly produced through fossil fuels. Alternatively, electrically driven heat pumps can exploit renewable power to recover environmental and waste heat, offering energy efficient and environmentally friendly heating and cooling for applications ranging from domestic and commercial buildings to process industries. For this reason, they are expected to play a primary role in complementing or displacing natural gas boilers in the residential and industrial sectors in the near future. Centrifugal compressors are already used as prime movers of the working fluid in heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low noise. However, they are subject to instabilities such as surge and stall like any other dynamic compressor and these phenomena develop quite differently than in classic open-loop systems such as gas turbines. In fact, such peculiarity is mainly due to the closed-loop configuration with real gases in two-phase conditions, occurring in typical heat pump cycles. In addition, heat exchangers also contribute to make these phenomena different from what is commonly studied. Compressor surge in closed-loop heat pump systems has received lower attention than other applications by the engineering community, lacking dedicated experimental characterization, and clear exposition of the phenomenon. The aim of this paper is to experimentally investigate the behavior of a centrifugal compressor installed into an innovative close loop heat pump system under stable and unstable conditions from both vibrational and fluid-dynamic points of view. The impact of the main process parameters on the evolution of the instability is shown, highlighting how surge cycles change by varying system operating conditions. The energy contents of surge cycles and pressure fluctuations are highlighted, using data postprocessing techniques such as fast Fourier transform and phase locked average. The vibro-acoustic analysis enrich the comprehension of the phenomena. The experimental results shown in this paper can be a basis for the future development of validated mathematical models of closed-loop heat pumps systems equipped with dynamic compressors operating under stable and unstable operating conditions.

The accelerating universe in a noncommutative analytically continued foliated quantum gravity

Abstract Based on an analytically continued Riemannian foliated quantum gravity super-Hamiltonian, known as branch cut quantum gravity (BCQG) we propose a novel approach to investigating the effects of noncommutative geometry on a minisuperspace of variables, influencing the acceleration behavior of the Universe’s wave function and the cosmic scale factor. Noncommutativity is introduced through a deformation of the conventional Poisson algebra, enhanced with a symplectic metric. The resulting symplectic manifold provides a natural setting that enables an isomorphism between canonically conjugate dual vector spaces, spanning the BCQG cosmic scale factor and its complementary quantum counterpart. Using this formulation, we describe the dynamic evolution of the Universe’s wave function, the cosmic scale factor, and its complementary quantum image. Our results strongly suggest that the noncommutative algebra induces late-time accelerated growth of the wave function, the Universe’s scale factor, and its complementary quantum counterpart, offering a new perspective on explaining the accelerating cosmic expansion rate and the inflationary period. In contrast to the inflationary model, where inflation requires a remarkably fine-tuned set of initial conditions in a patch of the Universe, analytically continued non-commutative foliated quantum gravity captures short and long scales, driving the evolutionary dynamics of the Universe through a reconfiguration of the primordial cosmic content of matter and energy. This reconfiguration is encapsulated into a quantum field potential, which leads to the generation of relic gravitational waves, a topic for future investigation. Graphical representations and contour plots indicate a characteristic torsion (or twist) deformation of spacetime geometry. This result introduces new speculative elements regarding the reconfiguration of matter and energy as a driver of spacetime torsion deformation, generating relic gravitational waves and serving as an alternative topological mechanism for the Universe’s acceleration. However, these assumptions require further investigation.

Full statistics of regularized local energy density in a freely expanding Kipnis–Marchioro–Presutti gas

Abstract We combine the Macroscopic Fluctuation Theory and the Inverse Scattering Method to determine the full long-time statistics of the energy density u ( x , t ) averaged over a given spatial interval, U = 1 2 L ∫ − L L d x u ( x , t ) , in a freely expanding Kipnis–Marchioro–Presutti (KMP) lattice gas on the line, following the release at t = 0 of a finite amount of energy at the origin. In particular, we show that, as time t goes to infinity at fixed L, the large deviation function of U approaches a universal, L-independent form when expressed in terms of the energy content of the interval | x | < L . A key part of the solution is the determination of the most likely configuration of the energy density at time t, conditional on U.

Use of butanol, pentanol and diesel in a compression ignition engine: A review

Using oxygenated alternative fuels in compression ignition (CI) engines is feasible for energy security problems and cli-mate change. Alcohols are regarded as alternative fuels for compression ignition engines because of their excellent physi-cochemical features, emission, and combustion characteristics. Research on alcohols and their additions has progressed significantly in recent years. Several researchers have examined the combined effect of higher alcohol with diesel and their impact and challenged that concentrations of higher alcohol reduce harmful particulate emissions in CI engines. This paper mainly focused on the performance and emissions properties of higher alcohols like butanol and pentanol. Alcohol has a low energy content, typically affecting engine brake-specific fuel consumption (BSFC). Low-temperature combustion (LTC) in compression ignition engines can lower NOx and smoke emissions, and improve the efficiency of the engine. LTC is done by combining higher alcohol with increased exhaust gas recirculation (EGR) rate and retarded fuel injection timing. The higher alcohol, along with the oxygen in the fuel reduces exhaust fumes, improves the air/fuel mixture by providing a longer ignition delay (ID), and can replace the fossil fuel like diesel (partially or whole) to allow efficient and clean combustion in CI engines. Finally, several significant findings and comments are provided regarding potential ave-nues for experimental research and future development. According to thorough analysis, bio-alcohols are considered to be a substitute fuel for CI engines.

Noise Source Identification for the Unsteady Low-Pressure Turbine Flow Fields

Abstract The article presents a data processing methodology to identify the noise sources in low-pressure turbine (LPT) stages and their relative importance. Scale adaptive simulation (SAS) has been carried out on a geometry reproducing the midspan blade section of an entire LPT stage. The proper orthogonal decomposition (POD) is applied to data matrices constructed with the velocity and the pressure fields in order to distinctly extract the coherent structures responsible for velocity fluctuations and pressure waves (i.e., POD modes from the corresponding kernel), their temporal evolution and energies. The cross-correlation matrices of the pressure modes and the velocity modes reveal the degree of coupling between pressure and velocity oscillations, thus highlighting the modes linked to the same flow phenomena. The results show that the periodic vortex shedding at the stator trailing edge emits strong pressure waves, and the upstream-propagating waves reflect against the adjacent stator suction surface. The POD modes related to the rotor–stator interaction show peak amplitudes at the blade passing frequency and its harmonics and their shapes mimic the potential interaction in the stator domain and the migration of viscous wakes in the rotor domain. The POD modes with lower energy content correspond to the stochastic turbulent structures originated from the turbulent boundary layers as well as those carried by the vane and blade wakes. The biggest noise sources of the current flow fields are identified to be the von Karman vortex street downstream the stator trailing edge and the rotor–stator interaction.

The Development and Characterisation of a Sustainable Plant-Based Sweet Spread Using Carob as a Cocoa and Sugar Replacement

Cocoa prices are predicted to rise continually, as demand remains high and there are supply issues caused by crop yield fluctuations. This study aimed to develop a sustainable plant-based sweet spread using functional plant-based ingredients, chickpeas and carob, as a cocoa and sugar alternative. Recipe optimisation resulted in the production of a control sample made using cocoa and three experimental samples containing varying proportions of carob (50%, 75%, and 100%). The samples were analysed for their physicochemical characteristics (water activity, pH, colour, and texture) and proximate composition (moisture, ash, carbohydrate, sugars, starch, protein, fat, and energy). Using carob as a cocoa substitute significantly decreased the pH, firmness and stickiness, fat and energy contents. On the other hand, increasing the percentage of carob led to a substantially higher sugar content in the sweet spreads. The results show the possibility of developing an innovative sustainable plant-based chocolate-flavoured spread with favourable physicochemical characteristics and nutritional profiles using carob powder and syrup as a cocoa and sugar replacement.

Chyme reinfusion therapy in adults with severe acute intestinal failure: A descriptive cohort study.

Chyme reinfusion therapy treats patients with high-output fistulas or stomas by returning chyme to the distal gut. The role of this treatment in severe acute intestinal failure is currently unclear. The primary outcome of this study was a successful establishment of chyme reinfusion therapy, defined by the ability to replace parenteral nutrition for nutrition support. A descriptive cohort study of adult patients with severe acute intestinal failure due to a high-output stoma and distal mucus fistula or a high-output small intestinal fistula receiving chyme reinfusion therapy was undertaken. The effect of chyme reinfusion therapy on parenteral nutrition requirements, medication, nutrition status, liver function, and treatment cost were studied. Twenty-four patients commenced treatment for a median of 44 (range, 3-571; total, 2263) days. Fifteen (62.5%) were successfully established for 1208 days, and nine continued treatment at home. Parenteral requirements, including volume, energy and nitrogen content, and frequency, were significantly reduced (P = 0.002), whereas anthropometric measurements remained stable. However, chyme therapy was not tolerated in nine patients (37.5%), and only two (8.3%) weaned fully from parenteral nutrition. Chyme reinfusion therapy was associated with a 47.6% reduction in parenteral energy requirements, 42.8% reduction in nitrogen, and 33.3% reduction in volume of parenteral nutrition requirements. Treatment was associated with a net cost of £30.05 ($40.27) per patient per day. Chyme reinfusion therapy was associated with reductions in the need for parenteral therapy and medication but did not replace parenteral nutrition or result in a significant cost saving.

Impact of Individuals' Biological and Meals' Nutritional Characteristics on the Thermic Effect of Food in Humans: Meta-Regression of Clinical Trials.

The thermic effect of food (TEF) may be a therapeutic target for the prevention and treatment of obesity. The impact of different biological and nutritional characteristics on TEF in humans was analyzed. The MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Latin American and Caribbean Health Sciences Literature databases were searched until November 2023 without language restrictions. Clinical trials were included that offered an oral test meal to adult and elderly individuals in a fasting state and measured TEF using calorimetry. The average TEF of each group was the outcome, and the impact of the individuals' and meal characteristics on the TEF was assessed using subgroups, meta-regression, and compositional analysis. The review included 133 studies, with 321 different groups. The mean TEF at 60 minutes after the test meal was 262 (95% CI, 236-288) kcal/d and decreased over time until 240 minutes after the test meal (P < .01). Male participants, individuals with normal body mass index, meals with energy content offered according to individual requirements, and meals with a mixed degree of food processing yielded a higher TEF. The total energy content of meals was the variable most strongly associated with TEF. Compositional analysis showed that the amount of lipids in meals was the only macronutrient consistently and negatively associated with TEF. The TEF is influenced by specific individuals' and meal characteristics. Total energy content and the amount of lipids were the characteristics of the meals most consistently associated with TEF. However, due to important methodological differences between studies, it is difficult to determine how to use TEF as a potential therapeutic target against obesity. PROSPERO registration no. CRD42023432504.

Evaluation of the Heat Transfer Performance of a Device Utilizing an Asymmetric Pulsating Heat Pipe Structure Based on Global and Local Analysis

PHPs (pulsating heat pipes) are widely used as an efficient heat transfer element in equipment thermal management and waste heat recovery due to their flexibility. The purpose of this study was to design a heat transfer device that utilizes an asymmetric pulsating heat pipe structure by adjusting the lengths of selected pipes within the entire circulation pipeline. In the experiment, a constant temperature water bath was used as the heat source, with heat dissipated in the condensing section via natural convection. An infrared thermal imager was used to record the temperature of the condensing section, and the local wall temperature distribution was measured in different channels of the condensing section. Based on an in-depth analysis of the wavelet frequency, the following research conclusions are drawn: Firstly, as the heat source temperature increases, the start-up time of the pulsating heat pipe is shortened, the operating state changes from start–stop–start to stable and continuous oscillation, and the oscillation mode changes from high amplitude and low frequency to low amplitude and high frequency. These changes are especially pronounced when the heat source temperature is 80 °C, which is when the thermal resistance reaches its lowest value of 0.0074 K/W, and the equivalent thermal conductivity reaches its highest value of 666.29 W/(m·K). Secondly, the flow and oscillation of the working fluid can be effectively promoted by appropriately shortening the length of the condensing section of the pulsating heat pipes or the heat transfer distance between the evaporation and condensing sections. Third, under a low-temperature heat source, the oscillation frequency of each channel of a pulsating heat pipe is found to be low based on wavelet analysis. However, as the heat source temperature increases, the energy content of the temperature signal of the working fluid in each channel changes from a low- to a high-frequency value, gradually converging to the same characteristic frequency. At this point, the working fluid in the pipes no longer flows randomly in multiple directions but rather in a single direction. Finally, we determined that the maximum oscillation frequency of working fluid in a PHP is around 0.7 HZ when using the water bath heating method.

The structure and dynamics of the laminar separation bubble

A novel selective mode decomposition, proper orthogonal decomposition and dynamic mode decomposition methods are used to analyse large-eddy simulation data of the flow field about a NACA0012 airfoil at low Reynolds numbers of $5\times 10^4$ and $9\times 10^4$ , and at near-stall conditions. The objective of the analysis is to investigate the structure of the laminar separation bubble (LSB) and its associated low-frequency flow oscillation (LFO). It is shown that the flow field can be decomposed into three dominant flow modes: two low-frequency modes (LFO-Mode-1 and LFO-Mode-2) that govern an interplay of a triad of vortices and sustain the LFO phenomenon, and a high-frequency oscillating (HFO) mode featuring travelling Kelvin–Helmholtz waves along the wake of the airfoil. The structure and dynamics of the LSB depend on the energy content of these three dominant flow modes. At angles of attack lower than the stall angle of attack and above the angle of a full stall, the flow is dominated by the HFO mode. At angles of attack above the stall angle of attack the LFO-Mode-2 overtakes the HFO mode, triggers instability in the LSB and initiates the LFO phenomenon. Previous studies peg the structure, stability and bursting conditions of the separation bubble to local flow parameters. However, the amplitude of these local flow parameters is dependent on the energy content of the three dominant flow modes. Thus, the present work proposes a more robust bursting criterion that is based on global eigenmodes.

The effect of Position and Availability interventions on adolescents' food choice: An online experimental study.

Interventions that alter characteristics of the food environment have been found to reduce energy intake in adults. However, few studies have examined the effect of Availability (reducing the number of higher energy options) and Position (altering the order of options) interventions on food choices by younger populations. Hence, this study examined the individual and combined effects of Availability and Position interventions on adolescents' energy selection from restaurant menus. In this online experiment, adolescents (13-17 years; N=434) were randomly assigned to one of four groups: (1) Availability and Position absent (control group) = 60% higher energy options, ordered randomly by energy content; (2) Availability present, Position absent = 40% higher energy options, ordered randomly by energy content; (3) Position present, Availability absent = 60% higher energy options, menu options were ordered from lower to higher energy; (4) Availability present, Position present = 40% higher energy options, menu options were ordered from lower to higher energy. The primary outcome was average energy selected per meal (starter, main, and dessert). Findings showed that both the Availability and Position interventions reduced adolescents' meal energy selection, whether presented as individual interventions or combined. Thus, reducing the availability of higher energy menu options, and ordering menu options from low to high energy, appear to be effective strategies for reducing adolescents' energy selection from overall meals. Further research is needed to determine whether these findings translate to real-life food choices.

Absolute Reference for Microwave Polarization Experiments. The COSMOCal Project and its Proof of Concept

Context. The cosmic microwave background (CMB), a remnant of the Big Bang, provides unparalleled insights into the primordial universe, its energy content, and the origin of cosmic structures. The success of forthcoming terrestrial and space experiments hinges on meticulously calibrated data. Specifically, the ability to achieve an absolute calibration of the polarization angles with a precision of <0.°1 is crucial to identify the signatures of primordial gravitational waves and cosmic birefringence within the CMB polarization. Aims. We introduce the COSmological Microwave Observations Calibrator project, designed to deploy a polarized source in space for calibrating microwave frequency observations. The project aims to integrate microwave polarization observations from small and large telescopes, ground-based and in space, into a unified scale, enhancing the effectiveness of each observatory and allowing robust combination of data. Methods. To demonstrate the feasibility and confirm the observational approach of our project, we developed a prototype instrument that operates in the atmospheric window centered at 260 GHz, specifically tailored for use with the NIKA2 camera at the IRAM 30 m telescope. Results. We present the instrument components and their laboratory characterization. The results of tests performed with the fully assembled prototype using a Kinetic Inductance Detectors-based instrument, similar concept of NIKA2, are also reported. Conclusions. This study paves the way for an observing campaign using the IRAM 30 m telescope and contributes to the development of a space-based instrument.

Nutritional values of soybean meal from different sources in multiparous sows

This study determined the available energy content, apparent total tract digestibility (ATTD) of nutrients, and ileal amino acid (AA) digestibility of soybean meal (SBM) from different sources in non-gestating, non-lactating sows. In Exp. 1, 24 multiparous Landrace × Yorkshire (LY) sows (parity 3–5) were allotted to a replicated 12 × 3 Youden square design consisting of 12 diets and 3 periods. The 12 diets included 11 test diets containing SBM from different sources and a corn-based diet. Each period included a 5-d adaptation and a 5-d total fecal and urine collection. In Exp. 2, 8 multiparous LY sows (parity 3–5) were allotted to a replicated 4 × 3 Youden square design with 4 diets and 3 periods. The 4 diets included a nitrogen-free diet and 3 SBM diets (3 representative SBM samples were selected from Exp. 1). Our results showed that the coefficient of variation of ether extract, crude fiber, neutral detergent fiber, and acid detergent fiber levels in 11 SBM samples were > 20%. There were no differences in digestible energy (DE), metabolizable energy (ME), and the ATTD of gross energy, nitrogen, and neutral detergent fiber values between different SBM samples (P > 0.05). Additionally, no differences in AA digestibility were identified among the 3 representative SBM samples (P > 0.05). In conclusion, there were no differences in DE, ME, and AA digestibility between different SBM samples fed to multiparous non-gestating sows. When formulating diets for sows, it is important to consider the differences in the nutritional value of SBM at different physiological stages.

Analyzing the impact of age on waste properties at an open dumpsite in Khulna

The rapid growth of the population has led to a significant increase in the amount of municipal solid waste (MSW), posing a burden and concern for our environment. Landfill mining as well as waste to energy could be a solution to this issue, but they require waste composition, particle size, and physiochemical and ultimate analysis are prerequisite requirements. Particle size was assessed through sieve analysis, categorizing MSW into ten different types followed by physiochemical and ultimate analyses. This study aimed to examine how the properties of MSW change with age. Findings showed that fine particles increased with age while larger particles decreased. With aging, certain physical components decreased, while others either increased or stayed constant. Organic content showed a significant decrease of 70.548% for fresh MSW and 0.35% for fifteen-year-old waste whereas plastic content remained almost constant after an increase from fresh MSW. Moisture content and volatile content of MSW reduced with age while fixed carbon and ash content increased with age. Ultimate analysis shows a drop of carbon, hydrogen, and nitrogen while oxygen shows a rise. Calorific value was found a decrease in trend with age indicating that the energy content of MSW reduced with age. A drastic reduction of unit weight was found in this study, dropping from 9.31 KN/m3 to 4.668 KN/m3. This study highlights the overall composition of MSW, the fluctuation in physiochemical analysis with age, and the sieve analysis and particle size distribution. It also displays the unit weight and the age-wise variation of the ultimate analysis. The findings of this study will aid landfill mining and waste to energy by providing comprehensive properties of MSW.

Towards improving the characteristics of high-energy pyrazines and their N-oxides.

Based on the methods of quantum chemistry and atom-atom potentials, the molecular and crystal structure of a number of high-energy pyrazines was modeled: unsubstituted diazines, as well as fully nitrated 1,4-diazabenzenes, their oxides and polymorphs. The enthalpies of formation, densities of molecular crystals, and some performance characteristics of these compounds were determined. The parameters of decomposition of substances were estimated. It has been established that tetranitropyrazine-1,4-dioxide has maximum energy content and excellent performance characteristics, which determine the prospects for using this compound as a high-energy one in the considered series of compounds. In this work, DFT calculations were conducted through the software Gaussian 09 using B3LYP functional with basis set aug-cc-PVDZ and the Grimme dispersion correction D2. For crystal structure optimization, the atom-atom potential methods with PMC program (Packing of Molecules in Crystal) were used. Charges for molecular electrostatic potential were fitted by FitMEP and enthalpies of formation in gas phase were assessed by G3B3.

Nutritive Value of Some Concentrate Feedstuffs for Guinea Pigs (Cavia porcellus).

The objective of this work was to ascertain the nutritive value of six concentrate feedstuffs commonly used in guinea pig feed manufacturing through the substitution method. Six test diets were obtained by replacing the corresponding basal mixture with 40% corn, 50% barley, 45% wheat bran, 35% soybean meal, 30% pigeon pea, or 30% Leucaena leaf meal. Sixty-three guinea pigs were randomly assigned to one of the nine experimental diets (three basal diets and six test diets, with seven animals per diet). The animals were housed in individual cages and provided with feed and water ad libitum. Following a ten-day adaptation period, the feed intake and faeces excretion were monitored for a further five days. The digestible energy content, expressed as kcal/kg dry matter (±standard error), was 3857 ± 83 for corn, 3454 ± 68 for barley, 2911 ± 110 for wheat bran, 3855 ± 81 for soybean meal, 3105 ± 79 for pigeon pea, and 2972 ± 72 for Leucaena leaf meal. The apparent total tract digestibility of crude protein, expressed as % (±standard error) was 73.8 ± 4.9 for corn, 69.5 ± 4.6 for barley, 76.4 ± 3.6 for wheat bran, 88.4 ± 1.0 for soybean meal, 62.1 ± 1.9 for pigeon pea, and 68.0 ± 1.8 for Leucaena leaf meal. Further research is required to increase knowledge about these and other feedstuffs for guinea pigs.

A new carbon-negative hydrogen production cycle for better sustainability

Carbon dioxide removal is considered by many as an essential piece to achieve global net zero targets which was also mentioned by the third working group of Intergovernmental Panel on Climate Change. On top of this, green hydrogen is badly needed to achive carbon-free society long-term sustainability. This study proposes a new five-step sodium hydroxide thermochemical cycle for simultaneous hydrogen production and carbon dioxide removal, which is driven by the heat at least 400 °C. The proposed integrated cycle can be driven by clean energy sources that can be utilized to generate heat at required temperatures. The proposed system is designed and analyzed by using energy and exergy approaches of thermodynamics. A case study is also developed in order to understand the effects of changing parameters on system performance. A thermochemical hydrogen production cycle is designed with an unequilibrium reaction where the respective heat capacity calculation models are employed. According to the calculations, more than half of the energy content of process heat can be converted into hydrogen, where maximum energy and exergy efficiencies of the thermochemical cycle are found as 50.05% and 76.61% when the separation reaction is carried out at 400 °C. According to the case study results, a parabolic trough collector type concentrated solar energy system with 295 kW of heat sink capacity, can generate 5216.65 kg of hydrogen and capture 19,991.97 kg of carbon dioxide in a location where 1500.11 kWh of solar energy is reached per m2 of area in a typical year.

Spatiotemporal structure of flow field by a dielectric-barrier-discharge plasma actuator using phase-resolved particle image velocimetry

A typical dielectric-barrier-discharge plasma actuator (DBD-PA) operating in continuous mode generates a self-similar starting vortex followed by a quasi-steady wall jet. In the burst mode, it generates periodic vortices, leading to a spatially wider mean flow field. The characteristics of periodic vortices can be controlled by adjusting the duty cycle α and burst frequency fb of the actuation signal. In the present study, the flow field generated by the actuator in burst mode is studied for 50%≥α≤90%, and 10 Hz ≥fb≤90 Hz. The Reynolds number of mean flow based on the maximum induced velocity and jet half-width ranges from 171 to 524. High-speed laser-sheet visualization and time-resolved particle image velocimetry are used for flow field measurements. The flow field generated during burst mode operation shows the strong influence of the burst frequency. Periodic vortices with comparable size and convection speed of starting vortex are generated at low fb. Dipoles and small-scale vortices are formed at moderate fb similar to the behavior of a transitional wall jet. Kelvin–Helmholtz instability is observed at higher burst frequency. An ornamental vortex consisting of several small periodic vortices is formed at high values of fb during the starting period. Based on the temporal evolution of momentum, the flow field generated by the DBD-PA can be classified into (i) starting flow regime, (ii) transitional flow regime, and (iii) periodic flow regime. The self-similarity of the mean flow field generated by the DBD-PA is verified by comparing the mean velocity profile at multiple downstream locations with the self-similar solutions of laminar and turbulent wall jets. The entrainment coefficient of the mean flow field is similar to that of an axisymmetric turbulent wall jet. The bi-orthogonal analysis shows that both coherent mode energy content and the entropy are minimum (about 5% only) for the continuous mode actuation. For the burst mode actuation, both the coherent mode energy content and the entropy are higher in magnitude compared to that of continuous mode and decrease with increasing burst frequency. The vortices in the periodic flow regime are locked in with fb. The distance between subsequent vortices, λx and flow frequency, f follow a power-law relationship, λx=cf−n, where c is a constant and n can be approximated as 2/3.

Wheeler-DeWitt canonical quantum gravity in hydrogenoid atoms according to de Broglie-Bohm and the geodesic hypothesis. Einstein’s Quantum Field Equation

We explore the geodesic hypothesis of orbital trajectories of the electrons in hydrogenoid atoms, in the frame of de Broglie-Bohm quantum theory. It is intended that the space-time can be curved, at very short distances, by the effect of the joint action of the energy content of the atomic system and the contribution of the electric and quantum potentials. The geodesic hypothesis would explain the non-lose of energy in the electron orbital trajectories. So we explore a conception where particles and waves interact in a closed system: the waves guide the particles and the particles generate the spacetime perturbation that acts as a wave, beyond the pilot-wave theory. We establish the equivalence, in a local neighborhood, between the electron trajectory of an hydrogenoid atom in the Minkowskian space where the de Broglie-Bohm can be cast with its movement in a Lorentzian manifold, according to the concept of metric tangent. Through the geodesic condition and the invariance of the elemental length, we establish a relationship between some components of the metrics. But as the particles in microphysics do not follow the Einstein’s field equation, we consider the 3+1 decomposition according to ADM and the quantization in the Wheeler De Witt theory and with a so-called quantum Einstein field equation, with a decomposition of spacetime into three-dimensional sheets of a spatial character. Then we derive from the moment-energy tensor a further equation between the components of the metrics. It opens the avenue to characterize the metric by an exact solution of the Einstein’s field equations.

Effect of a perforation on the flow characteristics of corrugated wall

The flow characteristics on a corrugated wall and the variations caused by a perforation are investigated experimentally based on two-dimensional particle image velocimetry (PIV), and the passive control mechanism of the perforation on the corrugated wall is studied. The corrugated wall has an amplitude-to-wavelength ratio 2a/λ = 0.1, with the wavelength Reynolds number Reλ = 14400 and bulk Reynolds number Reb = 17500. The perforation is located on the eleventh cycle of the corrugated wall. The results show that perforation increases the area of the recirculation zone, reduces the effect of frictional resistance, weakens the turbulence intensity and the Reynolds normal stress on the corrugated wall, but enhances the Reynolds shear stress. The POD and the Finite-Time Lyapunov Exponent(FTLE) are used to analyze the vortex structures. From the FTLE result, it can be seen that the perforation disturbs the original shear layer and redistributes the vortex structure of the flow field. The instantaneous fluctuating flow field of the first 50 % and the last 50 % of the energy content after POD mode decomposition is reconstructed to study the effect of perforation on on large and small scale structures in the flow field. It is found that the impact of perforation on small-scale structures is greater than that on large-scale structures.