RANS simulations of terrain-disrupted turbulent airflow at Hong Kong International Airport

Abstract Turbulent airflow mostly occurs at Hong Kong International Airport (HKIA) when winds blow off the hills on the Lantau Island (with peaks rising to almost 1000 m to the south of the airport) from the east to the southwest. In a previous study by Chan et al., turbulence intensity in terms of cube root of eddy dissipation rate (EDR1/3) was measured directly using a staring lidar beam. This paper extends the previous study to calculate the spatial distribution of EDR1/3 (the so-called EDR map), with the ultimate goal of monitoring the turbulence over all of the runway corridors of HKIA using the lidar. The EDR map is calculated based on plan position indicator (PPI) scans of the lidar. The whole scan area is divided into a number of small sectors, each having a size of about 1 km in range and 20° in azimuth. Velocity structure function is evaluated in every sector and compared with the theoretical von Kármán model to estimate the EDR1/3. This paper gives an overview of the calculation method, shows some examples of EDR map in terrain-disrupted turbulent airflow at HKIA, and examines the quality of the EDR1/3 value thus obtained by comparing against the measurements of a ground-based anemometer.

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Radiological features of body packers: An experience from a regional accident and emergency department in close proximity to the Hong Kong International Airport

Hong Kong Journal of Emergency Medicine ◽

10.1177/1024907918770083 ◽

2018 ◽

Vol 25 (4) ◽

pp. 202-210

Author(s):

Ho Kai Patrick Tsang ◽

Cheuk Kei Kathy Wong ◽

Oi Fung Wong ◽

Wing Lun William Chan ◽

Hing Man Ma ◽

...

Keyword(s):

Emergency Department ◽

Hong Kong ◽

Body Packing ◽

Radiological Features ◽

International Airport ◽

Accident And Emergency ◽

Accident And Emergency Department ◽

Body Packers ◽

Solid Form ◽

Hong Kong International Airport

Background: Body packing is a frequently used method for drug trafficking. Local information about the clinical and radiological features of body packing is lacking. Objectives: To evaluate the radiological features of body packers presenting to a hospital near to the Hong Kong International Airport and to compare the radiological features of solid form versus liquid cocaine. Methods: This was a retrospective cohort study. Medical notes of 269 suspected body packers, presenting to the Accident and Emergency Department of North Lantau Hospital under the detention by the law enforcement personnel from 1st January 2015 to 28th February 2017, were reviewed. The radiological features of body packing were retrospectively evaluated. Results: Sixty-nine cases were confirmed body packers radiographically. Majority of them (81%, 56/69) were cocaine packers. Powder form cocaine (67%, 49/69) was the most popular drug packed, followed by liquid cocaine (15%, 10/69). There was a trend of increasing incidence of liquid cocaine packers. The classical ‘double condom’, ‘tic tac’ and ‘halo’ signs were present in 94%, 72.5% and 42% of cases with radiologically confirmed body packing respectively. The ‘rosette’ sign was only identified in 1 case. Three new radiological signs, the ‘bag of eggs’, ‘lucent triangle’ and ‘black crescent’ sign, were suggested to aid identification of drug packets. The classical ‘tic tac’ sign was absent in all liquid cocaine packing cases (p<0.05). The liquid cocaine packets appeared irregular with indistinct border in majority of cases (p<0.05). The solid form packets were mostly opaque to faeces while liquid cocaine had variable density (p<0.05). Most solid form packets had homogeneous content which was in contrast to the heterogeneous content in liquid cocaine (p<0.05). Conclusion: Failure in detecting drug body packing may result in medicolegal consequences. Emergency physicians need to be aware of subtle radiological signs of liquid cocaine packets in the plain abdominal radiography.

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