Exploring the significance of domestic investment for foreign direct investment in China: a city-network approach

This paper uses a network approach and a negative binomial regression model (NBRM) to shed light on the association between Domestic Investment (DI) and Foreign Direct Investment (FDI) in interlinking Chinese cities in a space of flows. The empirical analysis is based on 2743 FDI and 9315 DI projects covering 77 Chinese cities. We address the question of what is the association between DI network measures and city attractiveness for FDI, and does the geographic distance of DI matter? While the physical distance of DI activity is found to have a negative association with FDI, city functional proximity and structural position in the DI network are found to have a positive association. We conclude that strategic policies to stimulate cross-territorial economic ties between Chinese cities should be advantageous in attracting inward foreign investment

Numerical modeling of a wire mesh for aerodynamic noise reduction

A novel wire mesh consisting of very fine wires and pores is numerically investigated for the purpose of noise reduction. To develop a numerical model for this wire mesh, a set of experimental flow-field data has been deployed for the model validation. The experimental data were measured with only 22% of the wind-tunnel cross section covered by the wire mesh, taking into account the vortex shedding from both sides of the wire-mesh fairing. It is found that existing wire-mesh models using a damping-type source term proportional to the square of flow velocity do not perform well in modeling this novel wire mesh. To tackle this issue, an improvement is proposed by additionally introducing a linear term to account for the permeability of the wire mesh, based on another set of experiments with the wind-tunnel cross section fully covered by the wire mesh. The proposed model is then validated against the experimental data, demonstrating its capability in modeling the wire mesh. Subsequently, the model is applied to a tandem cylinder configuration. Results show that a wide but short-span wire mesh significantly reduces the dominant tone of tandem cylinders, noise at higher frequencies, as well as the overall sound pressure levels

A fluid flow model for the pressure loss through perforated plates

A fluid flow through a perforated plate is a common problem in a wide variety of practical applications in thermal, mechanical, chemical, civil, nuclear, ocean and aerospace engineering. In this paper, we proposed a novel fluid flow model for the pressure loss through plates with circular perforations in both laminar and turbulent flows. The design of this model is based on the recent measurements conducted at ONERA in the framework of the on-going European Union H2020 INVENTOR project, as well as an existing model for laminar flows. The new model is then validated against existing numerical simulations in the laminar regime and experiments in the turbulent regime. Overall, the predictions given by the new model agree well with the numerical simulations and experiments, and are superior to other models in the literature. This is significant, considering that the present model is much simpler than these previous models. To demonstrate the application of the new model in numerical simulations, two-dimensional channel flows are simulated using Reynolds-averaged Navier-Stokes (RANS) equations with the new model as a pressure-drop source term added to the momentum equations. Results show that the RANS predictions agree very well with the present model predictions