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Galileo's Principle of Relativity (GPR) states that the laws of mechanics are the same in any inertial frame of reference. By determining that all inertial reference frames are equivalent, this principle implies a relativity of motion. On the other hand, even considering the GPR as fundamental for mechanics, Isaac Newton introduces the concepts of absolute time and space and presents arguments, of a dynamic nature, in defense of absolute motion, justified by the differentiation between inertial and non-inertial reference frames. The Special Relativity Theory (SRT) criticizes the notions of absolute time and space, but preserves the privileged role of inertial reference frames in the description of the laws of nature. Only with the General Relativity Theory (GRT) is equivalence established between all references, regardless of their state of motion and, thus, the notion of absolute motion is overthrown. This work aims to discuss the main doubts and issues that arise when studying the aforementioned concepts, as well as to investigate the apparent dubiousness between the PRG and the absolute movement. [ABSTRACT FROM AUTHOR]

This paper presents a proposition of a dual grid (DG)-based coupled deep reinforcement learning (DRL) and computational fluid dynamics (CFD) method for active flow control. The DG-DRL-CFD method uses a dual-resolution grid, with a coarser grid for the training phase and a finer grid for the testing phase of the DRL-CFD method. Further, after a validation study for our DRL-CFD-based parallelized in-house solvers, this paper presents a performance study for a periodic suction/ejection-based drag reduction for a cylinder in a channel-confined flow. Using an immersed boundary method for CFD on a Cartesian grid, this novel DG-DRL-CFD method is shown to result in almost same accuracy (within 1%) in a substantially reduced computational time as compared to the traditional DRL-CFD method (on the finer uniform grid). Finally, using a sharp interface level set method for an axisymmetric two-phase flow, this paper presents an application of the DR-DRL-CFD method for an oscillating base plate-based enhancement of heat transfer during nucleate pool boiling. As compared to our recent CFD study-based parametric study for the nucleate pool boiling problem, the present DG-DRL-CFD method leads to a profile and frequency of plate-oscillation that results in a larger value of average Nusselt number Nu avg for the plate. The coupled DRL-CFD method leads to plate oscillation profile giving higher enhancement in Nu avg , compared to an open-loop control strategy that involves a parametric sweep involving multiple simulations. • A dual grid (DG) based novel method is proposed which couples deep reinforcement learning and CFD for active flow control. • The method is validated on the problem of flow past cylinder with suction/ejection based drag reduction. • The method is applied to nucleate boiling with oscillating base plate where plate position is controlled using DRL. • The enhancement of Nusselt number is found to be higher than open-loop control strategy that involves a parametric sweep. [ABSTRACT FROM AUTHOR]

An extensive review of Einstein's theory of special relativity and his writings from today's scientific and philosophical perspectives found that at the turn of the 20th century, the scientific and philosophical views were not sufficiently developed to understand the problems that physicists faced and that Einstein tried to solve with his theory. Regardless how brilliant a scientist he was, in his pursuit, Einstein was guided by incorrect philosophical views; views prevalent at that time. These views misled him into an incorrect method and unrealistic theory with circular definitions, inconsistencies in the explanations and principles that contradict those developed from the empirical evidence. In particular, this study found that neither Einstein nor Poincare' expressed sufficiently the "inertial frames of reference" (coordinate systems) in their respective relativity principles. They expressed them in terms of the uniform movement of translation instead of absence of external forces. Because of that they both overlooked that fields generated in one frame of reference cause forces at a distance in the other frames of reference turning them into noninertial ones. Thus, their respective principles of relativity cannot be valid for field-based processes when field is generated outside of the frame of reference. Einstein's use of his relativity principle for conditions when it cannot be valid, in combination with an incorrect idealistic ontological view of the term "Law of Nature" and insufficient rationalistic understanding of the term "time," misled him into an incorrect method of developing his theory and to incorrect inferences of the other principles and concepts of this theory. Thus, the foundations of Einstein's theory of special relativity, his two postulates (principle of relativity and the invariance of velocity of light) as well as the relativity of simultaneity cannot be any longer justified. With that, Einstein's attempt to unify light and electromagnetism with mechanics, his concept of light, space, time and the whole theory of relativity with its other consequences cannot correctly represent the realities of the physical world. Apart from the philosophical, conceptual and logical problems of this theory, the invariance of velocity of light is in serious need for the experimental verification or refutation. Although the technology of Einstein's time was insufficient to carry out such test, it is technologically feasible to do so today. Therefore, it is recommended, and it should be of the utmost importance, for physicists to carry out such a test today. [ABSTRACT FROM AUTHOR]

• Single bubble nucleate boiling in zero gravity studied using level-set based numerical simulations. • Asymmetric sinusoidal motion of base plate leads to sustenance of bubble departure and nucleate boiling. • Nusselt number enhancement is observed due to counter-clockwise vortices impinging on base plate. • Coalascence of departing bubbles may be avoided within a certain parameter range for plate oscillations. This work presents Direct Numerical Simulations to study the effect of base plate oscillations on nucleate boiling heat transfer at low superheat, in the isolated bubble regime, under zero gravity conditions. An in-house solver, based on sharp interface dual grid level set method (SI-DGLSM), is used to carry out the numerical simulations. To enable nucleate boiling in zero gravity, an asymmetric periodic motion of the base plate is proposed, in which the average acceleration of the plate is different along the two plate-normal directions. This time-asymmetry in plate motion imparts net motion of bubbles away from the plate, which in turn sustains nucleate boiling. The departure of the bubble is presented first for cases with no phase change, where the effect of varying plate oscillation parameters on the departure of single bubble over the plate is studied for zero gravity conditions. Thereafter, the effect of the plate motion on nucleate boiling characteristics is presented, and the regime in which nucleate boiling is sustained is identified. We report the effect of plate motion on time series of bubble departure radius, Nusselt number and overall flow dynamics during nucleate boiling in zero gravity. The proposed technique for the sustenance of nucleate boiling in zero gravity conditions has numerous space-related applications for heat transfer enhancement. [ABSTRACT FROM AUTHOR]

The relationship of the circle to the ellipse in special relativity is investigated and the results used to derive a metric that can be applied to study rotating frames of reference. It is known that the form of Maxwell's electromagnetic equations in a gravitational field is produced by replacing ordinary differentiation by covariant differentiation of the electromagnetic field tensor. The Schwarzschild metric is usually used for covariant differentiation in the gravitational field. The metric used herein to give Maxwell's equations in a rotating system is derived from the properties of the Lorentz transformation. The electromagnetic field tensor proposed for the rotating system is symmetric with respect to the magnetic and the electric field. The electromagnetic equations that are produced for the rotating system yield solutions that give standing waves. These waves are finite, contained, and localized in a small region of space. It is suggested that particles of matter with the properties of billiard balls do not exist but packets of contained electromagnetic waves may have some of the properties of particles. One such property is inertia, because waves carry on in their existing state until they are changed by refraction, reflection, diffraction, or interference with other waves. Units are chosen so that the velocity of light is unity. The distance traveled by a light signal in an inertial frame of reference equals the time of travel. [ABSTRACT FROM AUTHOR]

The informational re-interpretation of the basic laws of the mechanics exploiting the Landauer principle is suggested. When a physical body is in rest or it moves rectilinearly with the constant speed, zero information is transferred; thus, the informational affinity of the rest state and the rectilinear motion with a constant speed is established. Inertial forces may be involved in the erasure/recording of information. The analysis of the minimal Szilard thermal engine as seen from the noninertial frame of references is carried out. The Szilard single-particle minimal thermal engine undergoes isobaric expansion relative to accelerated frame of references, enabling the erasure of 1 bit of information. The energy ΔQ spent by the inertial force for the erasure of 1 bit of information is estimated as Δ Q ≅ 5 3 k B T ¯ , which is larger than the Landauer bound but qualitatively is close to it. The informational interpretation of the equivalence principle is proposed: the informational content of the inertial and gravitational masses is the same. [ABSTRACT FROM AUTHOR]