Waldemar Wodziak

The Strata Mechanics Research Institute of the Polish Science Academy · Laboratory of Flow Metrology

This article presents an experimental stand for the generation of gas flows with very low velocities. The constant volume air flow was generated in the measurement area with the use of a Mariotte bottle and a water piston (water column in a tank). The air-flow velocity was determined from the change in the height of the water piston with time, whic...

This paper presents the results of PIV measurements of turbulent airflow in a channel with a single ribbed wall. The rough elements had the form of evenly spaced trapezoids. The ratio of the height of a single rib to the height of the measurement channel was 0.1. The ratio of the distance between adjacent ribs to the height of a single rib (i.e., t...

This paper presents a method of measuring gas flow velocity based on the thermal time-of-flight method. The essence of the solution is an analysis of the time shift and the shape of voltage signals at the transmitter and at a temperature wave detector. The measurements used a probe composed of a wave transmitter and a detector, both in the form of...

The experimental study with the use of particle image velocimetry (PIV) has been conducted to investigate the stability of flow around two identical square cylinders in tandem arrangement at a different Reynolds numbers. The important study parameter was the displacement of the downstream cylinder with velocity in range from Vc = 0.01 to 0.09 m/s....

The paper reports results of an analysis concerning the influence of a computational domain discretization method on the numerical stability of a model as well as the calculation error. The topology of a packed bed of a granular material consisting of granules contacting tangentially in one point makes the modelling of heat and mass transfer due to...

Computational domain discretization is the pre-processing stage in CFD analysis and it highly contributes to reducing the level of solution error as well as increasing the numerical stability of a model. The discretization of domain representing a packed bed of granular material is a demanding task due to the topology of the model consisting of sph...

This paper is about experimental study of air flow around two identical square cylinders arranged in tandem with the use of particle image velocimetry approach. Impact of progressive increase and progressive decrease in the spacing between centres of the cylinders (ranging from 2 to 9 widths of the cylinder) on a hysteresis limit were investigated....

Flow characteristics in vicinity of six circular cylinders aligned inline was investigated experimentally by means of PIV method. Experiments were conducted in a low speed closed circuit wind tunnel. Inflow velocity was 1.2 m/s which corresponds to Re=1600 based on the cylinder diameter. Spacing ratio between cylinders L/D was 1.5. Instantaneous an...

Flow characteristics in vicinity of six circular cylinders aligned inline was investigated experimentally by means of PIV method. Experiments were conducted in a low speed closed circuit wind tunnel. Inflow velocity was 1.2 m/s which corresponds to Re =1600 based on the cylinder diameter. Spacing ratio between cylinders L / D was 1.5. Instantaneous...

This study summarises the results of experimental testing and numerical simulations of airflow in a laboratory model of a blind channel aired by a forced ventilation system. The aim of the investigation is qualitative and quantitative verification of computer modelling data. The components of the velocity vector are measured using Particle Image Ve...

In copper mines, excavation chambers are ventilated by jet fans. A fan is installed at the inlet of the dead-end chamber, which is usually 20-30m long. The effectiveness of ventilation depends on the stream range generated by the fan. The velocity field generated by the supply air stream is fully three-dimensional and the flow is turbulent. Current...

This paper presents the results of experimental and numerical investigations of air flow through the crossing of a mining longwall and ventilation gallery. The object investigated consists of airways (headings) arranged in a T-shape. Maintained for technological purposes, the cave is exposed particularly to dangerous accumulations of methane. The l...

This paper presents the results of experimental and numerical investigations of air flow through the crossing of a mining longwall and ventilation gallery. The object investigated consists of airways (headings) arranged in a T-shape. Maintained for technological purposes, the cave is exposed particularly to dangerous accumulations of methane. The e...

This paper presents a comparison between results obtained using SPIV experimental technique and numerical simulations approach. An analysis has been performed to validate the turbulent models used in mining ventilation systems. The flow of air across the intersection of the mining face with the ventilation gallery has been examined.