Symmetric Shock Research Articles

Pareto-improving carbon-risk taxation

Summary Anthropogenic climate change produces two conceptually distinct negative economic externalities. The first is an expected path of climate damage. The second, the focus of this paper, is an expected path of economic risk. To isolate the climate-risk problem, we consider three mean-zero, symmetric shocks in our 12-period, overlapping generations model. These shocks impact dirty energy usage (carbon emissions), the relationship between carbon concentration and temperature and the connection between temperature and damages. By construction, our model exhibits a de minimis climate problem absent its shocks. However, due to non-linearities, symmetric shocks deliver negatively skewed impacts, including the potential for climate disasters. As we show, Pareto-improving carbon taxation can dramatically lower climate risk, in general, and disaster risk, in particular. The associated climate-risk tax, which is focused exclusively on limiting climate risk, can be as large as, or larger than, the carbon average-damage tax, which is focused exclusively on limiting average damage.

Dynamic measures of asymmetric & pairwise connectedness within an optimal currency area: Evidence from the ERM I system

This study introduces two novel metrics that calculate the degree of shock asymmetry which can be utilized to examine whether countries in a currency area face symmetric shocks. In an attempt to answer whether the symmetric shock assumption is fulfilled in the European case, the exchange rate transmission mechanism of all 14 countries that have joined the ERM and Sweden is explored. The findings point to the existence of two potential OCAs whereas the first and most stable one would be between Austria, Germany, and the Netherlands, and the extended second OCA would further include Belgium, Denmark, France, and Luxembourg.

Numerical Analysis of Side-loads Reduction in a Sub-scale Dual-bell Rocket Nozzle

A calibrated delayed detached eddy simulation of a sub-scale cold-gas dual-bell nozzle flow at high Reynolds number and in sea-level mode is carried out at nozzle pressure ratio NPR = 45.7. In this regime the over-expanded flow exhibits a symmetric and controlled flow separation at the inflection point, that is the junction between the two bells, leading to the generation of a low content of aerodynamic side loads with respect to conventional bell nozzles. The nozzle wall-pressure signature is analyzed in the frequency domain and compared with the experimental data available in the literature for the same geometry and flow conditions. The Fourier spectra in time and space (azimuthal wavenumber) show the presence of a persistent tone associated to the symmetric shock movement. Asymmetric modes are only slightly excited by the shock and the turbulent structures. The low mean value of the side-loads magnitude is in good agreement with the experiments and confirms that the inflection point dampens the aero-acoustic interaction between the separation-shock and the detached shear layer.

Odgovori monetarne i fiskalne politike u EU na krizu izazvanu kovidom 19

The COVID-19, or, the coronavirus crisis represents an unprecedented global threat in recent history that, as symmetric external shock, affects social and economic dynamics of different countries and regions on both macro and micro levels. The aim of the paper is to provide a critical overview of economic policy responses to the ongoing crisis in the EU and, in particular, the eurozone. The paper tends to answer the question whether proposed monetary and fiscal actions provide feasible risk mitigating tools for the ongoing crisis or are there some viable policy actions that are omitted?

Does Disclosure Lead to Lower Informed Trading and Symmetric Order-follow Shocks in the Tehran Stock Exchange?

Does Disclosure Lead to Lower Informed Trading and Symmetric Order-follow Shocks in the Tehran Stock Exchange?

Similarity solutions for strong shock waves in magnetogasdynamics under a gravitational field

In the present paper, we use a Lie group of transformations to obtain a class of similarity solutions to a problem of cylindrically symmetric strong shock waves propagating through one-dimensional, unsteady, and isothermal flow of a self-gravitating ideal gas under the influence of azimuthal magnetic field. The density of the ambient medium is assumed to be non-uniform ahead of the shock. The generators of the Lie group of transformations involve arbitrary constants which yield four different cases of possible solutions. Out of all possibilities, only two cases hold similarity solutions. One is with a power law shock path, and the other one is with an exponential law shock path. We present a detailed investigation for the case of power law shock path. Numerical computations have been performed to find out the flow patterns in the flow-field behind the shock. Also, we have analyzed the effects of variation in adiabatic index, ambient density exponent, gravitational parameter, and Alfven-Mach number on the flow variables behind the shock. All computations have been done using the software package MATLAB.

The COVID-19 Symmetric Shock, and Its Asymmetric Consequences

The outbreak of the COVID-19 pandemic is opening a period of policy uncertainties upon all us. The upcoming massive recession presents critical economic and financial variables, a steep rise of jobless claims, fixed-asset investment falling by 45% year on year, capital outflows from emerging markets by $ 83 bl. Buffers and shock absorbers are weak in several emerging and developing countries, and preventing the worst case scenario, a lengthy L shape recession, the size of the fiscal injection must be equivalent to the fall in the GDP. What can Caribbean countries do to mitigate the full impact of the pandemic tsunami? Jointly to Multilateral Development Banks, Caribbean governments should require core G20 Members to repurpose climate change investment plans, and, abide by their commitments. Lacking these actions, the COVID-19 shock would develop into a demand-driven slump, opening the door to a long stagnation.

Similarity Solutions for Imploding Shocks in a Non-ideal Magnetogasdynamics

In the present paper, we use a Lie group of transformations to obtain a class of similarity solutions to a problem of a cylindrically symmetric shock wave propagating through one-dimensional, unsteady flow of a non-ideal gas. We assume that the gas has infinite electrical conductivity under the influence of axial component of the magnetic field, with isothermal flow condition. The density of the ambient medium is taken to be uniform ahead of the shock. The generators of the Lie group of transformations involve arbitrary constants which yield two different cases of possible solutions with a power law shock path and exponential shock path. We present a detailed investigation for the case of power law shock path. Numerical computations have been carried out to find out the flow patterns in the flow-field behind the shock and the values of similarity exponent. Further, we compare the obtained similarity exponent with that obtained by Guderley’s (Luftfahrtforschung 19:302–312, 1942) method. The effects of the non-ideal parameter and magnetic field strength on the similarity exponent and the flow patterns have also been studied. All computations have been done using the software package MATHEMATICA.

Converging strong shock waves in magnetogasdynamics under isothermal condition

The similarity solutions to the problem of cylindrically symmetric strong shock waves in an ideal gas with a constant azimuthal magnetic field are presented. The flow behind the shock wave is assumed to spatially isothermal rather than adiabatic. We use the method of Lie group invariance to determine the possible class of self-similar solutions. Infinitesimal generators of Lie group transformations are determined by using the invariance surface conditions to the system and on the basis of arbitrary constants occurring in the expressions for the generators, four different possible cases of the solutions are reckoned and we observed that only two out of all possibilities hold self-similar solutions, one of which follows the power law and another follows the exponential law. To obtain the similarity exponents numerical calculations have been performed and comparison is made with the existing results in the literature. The flow patterns behind the shock are analyzed graphically.

Converging shock waves in a Van der Waals gas of variable density

SummaryThe converging problem of cylindrically or spherically symmetric strong shock wave collapsing at the axis/centre of symmetry, is studied in a non-ideal inhomogeneous gaseous medium. Here, we assume that the undisturbed medium is spatially variable and the density of a gas is decreasing towards the axis/centre according to a power law. In the present work, we have used the perturbation technique to the implosion problem and obtained a global solution that also admits Guderley’s asymptotic solution in a very good agreement which holds only in the vicinity of the axis/centre of implosion. The similarity exponents together with their corresponding amplitudes are determined by expanding the flow parameters in powers of time. We also refined the leading similarity exponents near the axis/centre of convergence. We compared our calculated results with the already existing results and found them in good agreements up to two decimal places. Shock position and flow parameters are analysed graphically with respect to the variation of values of different parameters. It is observed that an increase in the density variation index, adiabatic exponent and Van der Waals excluded volume, causes the time of shock collapse to decrease due to which the shock acceleration gets increased and shock reaches the axis/centre much faster.

Symmetric oil price shocks and government expenditure-real exchange rate nexus: ARDL and SVAR models for an oil-based economy, 1970–2018

Historically, oil has been the main source of earnings in the Saudi Arabian economy. Different from other symmetric oil price shock studies, the aim of this paper is to test the impacts of symmetri...

Informed trading, order flow shocks and the cross section of expected returns in Borsa Istanbul

ABSTRACTThis paper examines the relationship between information asymmetry and stock returns in Borsa Istanbul. For all stocks that are traded in Borsa Istanbul between March 2005 and April 2017, we estimate the probability of informed trading (PIN) to proxy for information asymmetry. Firm-level cross-sectional regressions indicate a statistically insignificant relationship between PIN estimates and future returns. Moreover, univariate and multivariate portfolio analyses assert that investors that hold stocks that have high information asymmetry do not obtain significant future returns. Consequently, our results suggest that information asymmetry proxied by PIN is a firm-specific risk and can be eliminated with portfolio diversification. Findings are robust to different factorizations in estimating PIN and free of any bias due to trade classification algorithms, boundary solutions, floating-point exceptions and symmetric order flow shocks.

Converging Cylindrical Symmetric Shock Waves in a Real Medium with a Magnetic Field

The topic “converging shock waves” is quite useful in Inertial Confinement Fusion (ICF). Most of the earlier studies have assumed that the medium of propagation is ideal. However, due to very high temperature at the axis of convergence, the effect of medium on shock waves should be taken in account. We have considered a problem of propagation of cylindrical shock waves in real medium. Magnetic field has been assumed in axial direction. It has been assumed that electrical resistance is zero. The problem can be represented by a system of hyperbolic Partial Differential Equations (PDEs) with jump conditions at the shock as the boundary conditions. The Lie group theoretic method has been used to find solutions to the problem. Lie’s symmetric method is quite useful as it reduces one-dimensional flow represented by a system of hyperbolic PDEs to a system of Ordinary Differential Equations (ODEs) by means of a similarity variable. Infinitesimal generators of Lie’s group transformation have been obtained by invariant conditions of the governing and boundary conditions. These generators involves arbitrary constants that give rise to different possible cases. One of the cases has been discussed in detail by writing reduced system of ODEs in matrix form. Cramer’s rule has been used to find the solution of system in matrix form. The results are presented in terms of figures for different values of parameters. The effect of non-ideal medium on the flow has been studied. Guderley’s rule is used to compute similarity exponents for cylindrical shock waves, in gasdynamics and in magnetogasdynamics (ideal medium), in order to set up a comparison with the published work. The computed values are very close to the values in published articles.

Asymmetric shockwave collisions in AdS5

Collisions of asymmetric planar shocks in maximally supersymmetric Yang-Mills theory are studied via their dual gravitational formulation in asymptotically anti-de Sitter spacetime. The post-collision hydrodynamic flow is found to be very well described by appropriate means of the results of symmetric shock collisions. This study extends, to asymmetric collisions, previous work of Chesler, Kilbertus, and van der Schee examining the special case of symmetric collisions [1]. Given the universal description of hydrodynamic flow produced by asymmetric planar collisions one can model, quantitatively, non-planar, non-central collisions of highly Lorentz contracted projectiles without the need for computing, holographically, collisions of finite size projectiles with very large aspect ratios. This paper also contains a pedagogical description of the computational methods and software used to compute shockwave collisions using pseudo-spectral methods, supplementing the earlier overview of Chesler and Yaffe [2].

Piston driven converging shock waves in a stiffened gas

The problem of a one-dimensional (1D) cylindrically or spherically symmetric shock wave converging into an inviscid, ideal gas was first investigated by Guderley[Starke kugelige und zylinrische verdichtungsstosse in der nahe des kugelmitterpunktes bzw. Der zylinderachse,” Luftfahrtforschung 19, 302 (1942)]. In the time since, many authors have discussed the practical notion of how Guderley-like flows might be generated. One candidate is a constant velocity, converging “cylindrical or spherical piston,” giving rise to a converging shock wave in the spirit of its classical, planar counterpart. A limitation of pre-existing analyses along these lines is the restriction to flows in materials described by an ideal gas equation of state (EOS) constitutive law. This choice is of course necessary for the direct comparison with the classical Guderley solution, which also features an ideal gas EOS. However, the ideal gas EOS is limited in its utility in describing a wide variety of physical phenomena and, in particular, the shock compression of solid materials. This work is thus intended to provide an extension of previous work to a nonideal EOS. The stiff gas EOS is chosen as a logical starting point due to not only its close resemblance to the ideal gas law but also its relevance to the shock compression of various liquid and solid materials. Using this choice of EOS, the solution of a 1D planar piston problem is constructed and subsequently used as the lowest order term in a quasi-self-similar series expansion intended to capture both curvilinear and nonideal EOS effects. The solution associated with this procedure provides correction terms to the 1D planar solution so that the expected accelerating shock trajectory and nontrivially varying state variable profiles can be obtained. This solution is further examined in the limit as the converging shock wave approaches the 1D curvilinear origin. Given the stiff gas EOS is not otherwise expected to admit a Guderley-like solution when coupled to the inviscid Euler equations, this work thus provides the semianalytical limiting behavior of a flow that cannot be otherwise captured using self-similar analysis.

Quantitative easing in a monetary union

Abstract The long season of unconventional monetary policies in advanced economies seems to be coming to an end. How can quantitative easing (QE) be effective where conventional monetary policy fails? How does it work in the peculiar environment of a monetary union? We study this latter case modelling a monetary union as the aggregate of two countries characterized by New Keynesian output and inflation relationships, with a Tobinian money market equation. QE is operated by the single central bank by expanding money supply in exchange for risky assets throughout the union. We assess the stabilization capacity of QE under different types of symmetric and asymmetric shocks, in which case fiscal accommodation at the country level should also intervene.

Characteristics analysis of rotor model with support–foundation looseness fault considering elastic–plastic contact

In this paper, the nonlinear response characteristics of a single degree of freedom lumped mass model with a new support looseness fault are analyzed. In this model, a new nonlinear contact stiffness model between the support and foundation is considered, which considers the elastic–plastic deformation of the contact parts. The nonlinear response of the system is obtained by numerical integration methods. The nonlinear results are compared with an asymmetric model and a piece-wise contact model. By comparing three different looseness fault models, the mechanism of generating multi-frequencies and fractional frequencies is analyzed. The result shows that plastic deformation makes the displacement amplitude increase rapidly; odd harmonics appear in symmetric stiffness model due to the modulation of symmetric shock forces; however, harmonic response appears in asymmetric stiffness model; when the contact number is odd, the frequency components contain odd or even order fractional frequencies at supercritical speeds due to the incompatibility of contacts on the upper and lower surfaces; when the contact number is even, multiple frequency components appear at subcritical frequencies.

Spherically Symmetric Shock Waves in Materials with a Nonlinear Stress-Strain Dependence

The paper considers the dynamic deformation features of constructional materials with nonlinear stress-strain dependence. For the one-dimensional shock waves with nonzero curvature arising in constructions under dynamic loading the propagation regularities are studied on the basis of the matched asymptotic expansions method. In the nonstationary problem with the longitudinal spherical shock wave the relations for simultaneous consideration of dynamic properties in the outer and inner problem of the perturbation method are obtained. The solution in the front-line area is constructed on the basis of the evolution equation different from ones for a plane longitudinal wave. The need for a solving of an additional ODE system for matching outer and inner expansions is shown. It is obtained that the outer solution asymptotics in the spherically symmetric problem contains waves reflected from the leading front in contrast to the solution behavior behind the front of the plane shock wave.

Global Conic Shock Wave for the Steady Supersonic Flow Past a Curved Cone

In this paper, we establish the global existence of a steady symmetric conic shock wave when a supersonic incoming flow hits a symmetric cone for a steady potential flow. The speed of the incoming flow is close to the limit speed, and the generatrix of the cone is assumed to have an attack angle less than a critical value and to have a decay rate on its second order derivatives. Based on a background solution, which is introduced here for the first time, we apply the characteristic method to construct the global solution.

Euro area growth differentials: diverging and reinforcing factors in a Kaleckian SVAR approach

The aim of this paper is to identify the euro area economic heterogeneity by disentangling the factors and characteristics shaping and exacerbating growth differentials between surplus and deficit countries. The five Kaleckian determinants of profits are used in the paper as the interpretative framework to assess the sources of divergence. According to an SVAR methodology, eight diverging factors and six reinforcing factors were detected as drivers of the differentials. It follows that the two regions represent different economic structures and that this dichotomy, in turn, means that symmetric shocks have asymmetric effects, while asymmetric shocks reinforce the regional differences. An endogenous investment-GDP feedback process and an investment–unemployment loop are mutually reinforcing mechanisms, which impair the production base and constrain future growth, so temporary shocks have long-lasting effects. The analysis emphasizes the need to rethink the European macro mechanism and to achieve a common and shared macro strategy that goes beyond national political interests and inclusively pursues the same objective: convergence.