A problem occurred while using AWAS

zhuzhu

When I used the active absorption wave generation method AWAS, I found that piston would gradually move away from the water when the simulation time reached the time when AWAS was enabled. Here's my code. Why?

<?xml version="1.0" encoding="UTF-8" ?>

<case>

  <casedef>

    <constantsdef>      

      <gravity x="0" y="0" z="-9.81" comment="Gravitational acceleration" units_comment="m/s^2" />

      <rhop0 value="1000" comment="Reference density of the fluid" units_comment="kg/m^3" />

      <hswl value="0" auto="true" comment="Maximum still water level to calculate speedofsound using coefsound" units_comment="metres (m)" />

      <gamma value="7" comment="Polytropic constant for water used in the state equation" />

      <speedsystem value="0" auto="true" comment="Maximum system speed (by default the dam-break propagation is used)" />

      <coefsound value="20" comment="Coefficient to multiply speedsystem" />

      <speedsound value="0" auto="true" comment="Speed of sound to use in the simulation (by default speedofsound=coefsound*speedsystem)" />

      <coefh value="1.2" comment="Coefficient to calculate the smoothing length (h=coefh*sqrt(3*dp^2) in 3D)" />

      <cflnumber value="0.2" comment="Coefficient to multiply dt" />

    </constantsdef>

    <mkconfig boundcount="241" fluidcount="9">

        <mkorientfluid mk="0" orient="Xyz" />

    </mkconfig>

    <geometry>

      <definition dp="0.5" comment="Initial inter-particle distance" units_comment="metres (m)">

        <pointmin x="-10.0" y="0.0" z="-5.0" />

        <pointmax x="220.0" y="0.0" z="60.0" />

      </definition>

      <commands>

        <mainlist>

        <setshapemode>actual | dp | bound</setshapemode>

        <setmkbound mk="0"/>

        <setdrawmode mode="face"/>

        <drawbox objname="box">

          <boxfill>solid</boxfill>

          <point x="0.0" y="-5.0" z="0.0" />

          <size x="210.0" y="10.0" z="55.0" />

        </drawbox>

        <setmkbound mk="1"/>

        <setdrawmode mode="solid"/>

        <drawbox objname="sand">

          <boxfill>solid</boxfill>

          <point x="0.0" y="-5.0" z="0.0" />

          <size x="210.0" y="10.0" z="30.0" />

        </drawbox>

        <setmkbound mk="2"/>

        <setdrawmode mode="full"/>

        <drawbox objname="piston">

          <boxfill>solid</boxfill>

          <point x="5.0" y="-5.0" z="30.0" />

          <size x="0.4" y="10.0" z="24.0" />

        </drawbox>

        <move x="0.0" y="-5.0" z="30.0" />

        <setmkfluid mk="0"/>

        <fillbox x="110.0" y="5.0" z="5.0" objname="FillBox">

          <modefill>void</modefill>

          <point x="0" y="0" z="0" />

          <size x="210.0" y="10.0" z="20.0" />

        </fillbox>

        <matrixreset />

        <shapeout file="" />

        </mainlist>

      </commands>

    </geometry>

    <motion>

      <objreal ref="2">

        <begin mov="1" start="0"/> 

        <mvnull id="1" />

      </objreal>

    </motion>

  </casedef>

  <execution>

    <special>

      <wavepaddles>

        <piston>

          <mkbound value="2" comment="Mk-Bound of selected particles" />

          <start value="0" comment="Start time (default=0)" />

          <duration value="0.0" comment="Movement duration, Zero is the end of simulation (default=0)" />

          <depth value="20.0" comment="Water depth (default=0)" />

          <pistondir x="1.0" y="0.0" z="0.0" comment="Movement direction (default=(1,0,0))" />

          <waveorder value="2" comment="Order wave generation 1:1st order, 2:2nd order (default=1)" />

          <waveheight value="2.0" comment="Wave height" />

          <waveperiod value="10.0" comment="Wave period" />

          <phase value="0.0" comment="Initial wave phase in function of PI (default=0)" />

          <ramp value="1" comment="Periods of ramp (default=0)" />

          <savemotion periods="24" periodsteps="20" xpos="2.0" zpos="-0.15" comment="Saves motion data. xpos and zpos are optional. zpos=-depth of the measuring point" />

          <awas_zsurf>

            <startawas value="10" comment="Time to start AWAS correction (def=ramp*waveperiod)" />

            <swl value="20" comment="Still water level (free-surface water)" />

            <elevation value="2" comment="Order wave to calculate elevation 1:1st order, 2:2nd order (def=2)" />

            <gaugex valueh="10" comment="Position in X from piston to measure free-surface water (def=5*Dp)" />

            <gaugey value="0" comment="Position in Y to measure free-surface water" />

            <gaugezmin value="46" comment="Minimum position in Z to measure free-surface water, it must be in water (def=domain limits)" />

            <gaugezmax value="54" comment="Maximum position in Z to measure free-surface water (def=domain limits)" />

            <gaugedp value="0.25" comment="Resolution to measure free-surface water, it uses Dp*gaugedp (def=0.1)" />

            <coefmasslimit value="0.4" comment="Coefficient to calculate mass of free-surface (def=0.5 on 3D and 0.4 on 2D)" />

            <savedata value="1" comment="Saves CSV with information 1:by part, 2:more info 3:by step (def=0)" />

            <limitace value="2" comment="Factor to limit maximum value of acceleration, with 0 disabled (def=2)" />

            <_correction coefstroke="1.8" coefperiod="1" powerfunc="3" comment="Drift correction configuration (def=no applied)" />

          </awas_zsurf>

</piston>

      </wavepaddles>

    </special>

   

Asalih3d

You have used bad parameters for AWAS

Start with the initial example and play with parameters until you understand what each of them do.

Kind regards

Asalih3d

Also note the "_"

Infront of some of your parameters. It means they are not applied!